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א לוּלָאָה הוא מבנה בקרת תכנות המאפשר לך לבצע א גוש קוד ללא הגבלת זמן אם מתקיים תנאי מסוים. לולאות משמשות לביצוע פעילויות חוזרות ולהגביר את ביצועי התכנות. ישנן מספר לולאות בשפת התכנות C, אחת מהן היא לולאת 'עשה תוך כדי' .

א לולאת 'עשה תוך כדי' הוא צורה של א לוּלָאָה ב-C שמבצע את בלוק הקוד ראשון, ואחריו התנאי. אם התנאי הוא נָכוֹן , ה לוּלָאָה ממשיך לרוץ; אחרת, זה מפסיק. עם זאת, האם התנאי הוא במקור נָכוֹן , הוא מבטיח שבלוק הקוד מבוצע לפחות פעם אחת.

תחביר לעשות תוך לולאה

התחביר של לולאת ה-Do-While בשפת C ניתן להלן:

 do{ //code to be executed }while(condition); 

המרכיבים מחולקים לחלקים הבאים:

שיטות Java arraylist

• ה לעשות מילת מפתח מסמן את תחילת הלופ.
• ה בלוק קוד בְּתוֹך סוגריים מסולסלים {} הוא גוף הלולאה, שמכיל את הקוד שברצונך לחזור עליו.
• ה תוך מילת מפתח אחריו מופיע תנאי מוקף בסוגריים (). לאחר הפעלת בלוק הקוד, מצב זה מאומת. אם התנאי הוא נָכוֹן , הלולאה ממשיכה אחרת, ה לולאה מסתיימת .

עבודה של do while Loop ב-C

הבה נסתכל על דוגמה כיצד א לולאת עשה תוך כדי עובד ב-C. בדוגמה זו, נכתוב תוכנית פשוטה שתשאל את המשתמש עבור א סיסמה וממשיך לשאול עד שהסיסמה הנכונה מוזנת.

דוגמא:

 #include #include int main() { char password[] = 'secret'; char input[20]; do { printf('Enter the password: '); scanf('%s', input); } while (strcmp(input, password) != 0); printf('Access granted!
'); return 0; } 

התוכנית פועלת באופן הבא:

1. קובצי הכותרות הבאים כלולים: לסטנדרט קֶלֶט ו תְפוּקָה שגרות ו עבור מחרוזת פונקציות מניפולציה .
2. הסיסמה הנכונה מוגדרת כ-a מערך תווים (סיסמת תווים[]) עם הערך 'סוֹד'
3. לאחר מכן, אנו מגדירים קלט מערך תווים נוסף לאחסון הקלט של המשתמש.
4. ה לעשות מילת מפתח מציין שבלוק הקוד הכלול ב- לוּלָאָה יבוצע לפחות פעם אחת.
5. משתמש ב הפונקציה printf() , אנו מציגים הנחיה המבקשת מהמשתמש להזין את הסיסמה שלו בתוך הלולאה.
6. לאחר מכן, אנו קוראים את הקלט של המשתמש משתמש ב פונקציית scanf() ולאחסן אותו ב מערך קלט .
7. לאחר קריאת ה קֶלֶט , אנו משתמשים ב- strcmp() פונקציה כדי להשוות את הקלט עם הסיסמה הנכונה. אם המיתרים כן שווה, ה פונקציית strcmp מחזירה 0. לכן, אנו ממשיכים בלולאה כל עוד הקלט והסיסמה אינם שווים.
8. פעם ה סיסמה נכונה נכנסים, הלולאה מסתיימת ואנחנו מדפיסים 'כניסה מורשית!' משתמש ב הפונקציה printf() .
9. לאחר מכן, התוכנית מחזירה 0 כדי לציין ביצוע מוצלח.

תְפוּקָה:

הבה נעבור על תרחיש אפשרי:

 Enter the password: 123 Enter the password: abc Enter the password: secret Access Granted! 

הֶסבֵּר:

בדוגמה זו, המשתמש מזין תחילה את הסיסמאות השגויות, '123' ו 'א ב ג' . הלולאה מבקשת מהמשתמש עד לסיסמה הנכונה 'סוֹד' נכנס. ברגע שהסיסמה הנכונה מסופקת, הלולאה מסתיימת, וה- 'כניסה מורשית!' ההודעה מוצגת.

דוגמה ללולאת do while ב-C:

דוגמה 1:

הנה דוגמה פשוטה של ​​א לולאת 'עשה תוך כדי' ב-C שמדפיס מספרים מ-1 עד 5:

 #include int main() { inti = 1; do { printf('%d
&apos;, i); i++; } while (i<= 5); return 0; } < pre> <p> <strong>Output:</strong> </p> <pre> 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the <strong> <em>code block</em> </strong> within the do loop will be executed at least once, printing numbers from <strong> <em>1 to 5</em> </strong> . After each iteration, the <strong> <em>i value</em> </strong> is incremented, and the condition <strong> <em>i<= 5< em> </=></em></strong> is checked. If the condition is still true, the loop continues; otherwise, it terminates.</p> <p> <strong>Example 2:</strong> </p> <p>Program to print table for the given number using do while Loop</p> <pre> #include intmain(){ inti=1,number=0; printf(&apos;Enter a number: &apos;); scanf(&apos;%d&apos;,&amp;number); do{ printf(&apos;%d 
&apos;,(number*i)); i++; }while(i<=10); return 0; } < pre> <p> <strong>Output:</strong> </p> <pre> Enter a number: 5 5 10 15 20 25 30 35 40 45 50 Enter a number: 10 10 20 30 40 50 60 70 80 90 100 </pre> <p> <strong>Example 3:</strong> </p> <p>Let&apos;s take a program that prints the multiplication table of a given number N using a <strong> <em>do...while Loop</em> :</strong> </p> <pre> #include int main() { int N; printf(&apos;Enter a number to generate its multiplication table: &apos;); scanf(&apos;%d&apos;, &amp;N); inti = 1; do { printf(&apos;%d x %d = %d
&apos;, N, i, N * i); i++; } while (i<= 10); return 0; } < pre> <p> <strong>Output:</strong> </p> <p>Let us say you enter the number 7 as input:</p> <pre> Please enter a number to generate its multiplication table: 7 7 x 1 = 7 7 x 2 = 14 7 x 3 = 21 7 x 4 = 28 7 x 5 = 35 7 x 6 = 42 7 x 7 = 49 7 x 8 = 56 7 x 9 = 63 7 x 10 = 70 </pre> <p>The program calculates and prints the multiplication table for <strong> <em>7</em> </strong> from 1 to 10.</p> <h3>Infinite do while loop</h3> <p>An <strong> <em>infinite loop</em> </strong> is a loop that runs indefinitely as its condition is always <strong> <em>true</em> </strong> or it lacks a terminating condition. Here is an example of an <strong> <em>infinite do...while loop</em> </strong> in C:</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { inti = 1; do { printf(&apos;Iteration %d
&apos;, i); i++; } while (1); // Condition is always true return 0; } </pre> <p>In this <strong> <em>example</em> </strong> , the <strong> <em>loop</em> </strong> will keep running <strong> <em>indefinitely</em> </strong> because <strong> <em>condition 1</em> </strong> is always <strong> <em>true</em> </strong> .</p> <p> <strong>Output:</strong> </p> <p>When you run the program, you will see that it continues printing <strong> <em>&apos;Iteration x&apos;,</em> </strong> where x is the <strong> <em>iteration number</em> </strong> without stopping:</p> <pre> Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 ... (and so on) </pre> <p>To interrupt an infinite loop like this, you generally use a <strong> <em>break statement</em> </strong> within the <strong> <em>loop</em> </strong> or some external condition you can control, such as <strong> <em>hitting</em> </strong> a specific key combination. In most desktop settings, the keyboard shortcut <strong> <em>Ctrl+C</em> </strong> can escape the Loop.</p> <h3>Nested do while loop in C</h3> <p>In C, we take an example of a <strong> <em>nested do...while loop</em> </strong> . In this example, we will write a program that uses <strong> <em>nested do...while loops</em> </strong> to create a numerical pattern.</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { int rows, i = 1; printf(&apos;Enter the number of rows: &apos;); scanf(&apos;%d&apos;, &amp;rows); do { int j = 1; do { printf(&apos;%d &apos;, j); j++; } while (j <= i); printf('
'); i++; } while (i<="rows);" return 0; < pre> <p>In this program, we use <strong> <em>nested do...while loops</em> </strong> to generate a pattern of numbers. The <strong> <em>outer loop</em> </strong> controls the number of rows, and the <strong> <em>inner loop</em> </strong> generates the numbers for each row.</p> <p> <strong>Output:</strong> </p> <p>Let us say you input five as the number of rows:</p> <pre> Enter the number of rows: 5 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the program generates a pattern of numbers in a <strong> <em>triangular shape</em> </strong> . The <strong> <em>outer loop</em> </strong> iterates over the rows, and the <strong> <em>inner loop</em> </strong> iterates within each row, printing the numbers from 1 up to the current row number.</p> <h2>Difference between while and do while Loop</h2> <p>Here is a tabular comparison between the while loop and the do-while Loop in C:</p> <table class="table"> <tr> <th>Aspect</th> <th>while loop</th> <th>do-while loop</th> </tr> <tr> <td> <strong>Syntax</strong> </td> <td>while (condition) { ... }</td> <td>do { ... } while (condition);</td> </tr> <tr> <td> <strong>Loop Body Execution</strong> </td> <td>Condition is checked before execution.</td> <td>The body is executed before the condition.</td> </tr> <tr> <td> <strong>First Execution</strong> </td> <td>The condition must be true initially.</td> <td>The body is executed at least once.</td> </tr> <tr> <td> <strong>Loop Execution</strong> </td> <td>May execute zero or more times.</td> <td>Will execute at least once.</td> </tr> <tr> <td> <strong>Example</strong> </td> <td>while (i<5) { printf('%d
', i); i++; }< td> <td>do { printf(&apos;%d
&apos;, i); i++; } while (i<5);< td> </5);<></td></5)></td></tr> <tr> <td> <strong>Common Use Cases</strong> </td> <td>When the loop may not run at all.</td> <td>When you want the loop to run at least once.</td> </tr> </table> <p> <strong>While Loop:</strong> The loop body is executed before the condition is checked. If the condition is initially <strong> <em>false</em> </strong> , the loop may not execute.</p> <p> <strong>Do-while Loop:</strong> The <strong> <em>loop body</em> </strong> is executed at least once before the condition is <strong> <em>checked</em> </strong> . This guarantees that the loop completes at least one iteration.</p> <p>When you want the <strong> <em>loop</em> </strong> to run based on a condition that may be <strong> <em>false</em> </strong> at first, use the <strong> <em>while loop</em> </strong> , and when you want the loop to run at least once regardless of the starting state, use the <strong> <em>do-while loop.</em> </strong> </p> <h2>Features of do while loop</h2> <p>The do-while loop in C has several fundamental characteristics that make it an effective programming technique in certain situations. The following are the significant characteristics of the do-while loop:</p> <ul> <tr><td>Guaranteed Execution:</td> Unlike other <strong> <em>loop structures</em> </strong> , the <strong> <em>do-while oop</em> </strong> ensures that the loop body is executed at least once. Because the condition is assessed after the loop body, the code within the loop is performed before the condition is verified. </tr><tr><td>Loop after testing:</td> The <strong> <em>do-while loop</em> </strong> is a post-tested loop which implies that the loop condition is assessed after the loop body has been executed. If the condition is true, the loop body is run once again. This behavior allows you to verify the condition for repetition before ensuring that a given activity is completed. </tr><tr><td>Conditionally Controlled:</td> The loop continues to execute as long as the condition specified after the while keyword remains <strong> <em>true</em> </strong> . When the condition evaluates to <strong> <em>false</em> </strong> , the loop is terminated, and control shifts to the sentence after the loop. </tr><tr><td>Flexibility:</td> The <strong> <em>do-while loop</em> </strong> may be utilized in several contexts. It is typically used in cases where a piece of code must be executed at least once, such as <strong> <em>menu-driven programs, input validation,</em> </strong> or <strong> <em>repetitive computations</em> </strong> . </tr><tr><td>Nesting Capability:</td> Similar to other <strong> <em>loop constructs</em> </strong> , the <strong> <em>do-while loop</em> </strong> can be <strong> <em>nested</em> </strong> inside other <strong> <em>loops</em> </strong> or <strong> <em>control structures</em> </strong> to create more complex control flow patterns. It allows for the creation of <strong> <em>nested loops</em> </strong> and the implementation of intricate repetitive tasks. </tr><tr><td>Break and Continue:</td> The break statement can be used within a <strong> <em>do-while loop</em> </strong> to terminate the loop execution and exit the loop prematurely. The <strong> <em>continue statement</em> </strong> can skip the remaining code in the current iteration and jump to the next iteration of the loop. </tr><tr><td>Local Scope:</td> Variables declared inside the <strong> <em>do-while loop</em> </strong> body have local scope and are accessible only within the <strong> <em>loop block.</em> </strong> They cannot be accessed outside the loop or by other loops or control structures. </tr><tr><td>Infinite Loop Control:</td> It is crucial to ensure that the loop&apos;s condition is eventually modified within the <strong> <em>loop body</em> </strong> . This modification is necessary to prevent infinite loops where the condition continually evaluates to true. Modifying the condition ensures that the loop terminates at some point. </tr></ul> <hr></=></pre></=></pre></=10);></pre></=>

הֶסבֵּר:

בדוגמה זו, ה בלוק קוד בתוך לולאת do יבוצע לפחות פעם אחת, הדפסת מספרים מ 1 עד 5 . לאחר כל איטרציה, ה אני מעריך מוגדל, והמצב אני<= 5< em> נבדק. אם התנאי עדיין נכון, הלולאה ממשיכה; אחרת, הוא מסתיים.

דוגמה 2:

תוכנית להדפסת טבלה עבור המספר הנתון באמצעות do while Loop

 #include intmain(){ inti=1,number=0; printf('Enter a number: '); scanf('%d',&number); do{ printf('%d 
&apos;,(number*i)); i++; }while(i<=10); return 0; } < pre> <p> <strong>Output:</strong> </p> <pre> Enter a number: 5 5 10 15 20 25 30 35 40 45 50 Enter a number: 10 10 20 30 40 50 60 70 80 90 100 </pre> <p> <strong>Example 3:</strong> </p> <p>Let&apos;s take a program that prints the multiplication table of a given number N using a <strong> <em>do...while Loop</em> :</strong> </p> <pre> #include int main() { int N; printf(&apos;Enter a number to generate its multiplication table: &apos;); scanf(&apos;%d&apos;, &amp;N); inti = 1; do { printf(&apos;%d x %d = %d
&apos;, N, i, N * i); i++; } while (i<= 10); return 0; } < pre> <p> <strong>Output:</strong> </p> <p>Let us say you enter the number 7 as input:</p> <pre> Please enter a number to generate its multiplication table: 7 7 x 1 = 7 7 x 2 = 14 7 x 3 = 21 7 x 4 = 28 7 x 5 = 35 7 x 6 = 42 7 x 7 = 49 7 x 8 = 56 7 x 9 = 63 7 x 10 = 70 </pre> <p>The program calculates and prints the multiplication table for <strong> <em>7</em> </strong> from 1 to 10.</p> <h3>Infinite do while loop</h3> <p>An <strong> <em>infinite loop</em> </strong> is a loop that runs indefinitely as its condition is always <strong> <em>true</em> </strong> or it lacks a terminating condition. Here is an example of an <strong> <em>infinite do...while loop</em> </strong> in C:</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { inti = 1; do { printf(&apos;Iteration %d
&apos;, i); i++; } while (1); // Condition is always true return 0; } </pre> <p>In this <strong> <em>example</em> </strong> , the <strong> <em>loop</em> </strong> will keep running <strong> <em>indefinitely</em> </strong> because <strong> <em>condition 1</em> </strong> is always <strong> <em>true</em> </strong> .</p> <p> <strong>Output:</strong> </p> <p>When you run the program, you will see that it continues printing <strong> <em>&apos;Iteration x&apos;,</em> </strong> where x is the <strong> <em>iteration number</em> </strong> without stopping:</p> <pre> Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 ... (and so on) </pre> <p>To interrupt an infinite loop like this, you generally use a <strong> <em>break statement</em> </strong> within the <strong> <em>loop</em> </strong> or some external condition you can control, such as <strong> <em>hitting</em> </strong> a specific key combination. In most desktop settings, the keyboard shortcut <strong> <em>Ctrl+C</em> </strong> can escape the Loop.</p> <h3>Nested do while loop in C</h3> <p>In C, we take an example of a <strong> <em>nested do...while loop</em> </strong> . In this example, we will write a program that uses <strong> <em>nested do...while loops</em> </strong> to create a numerical pattern.</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { int rows, i = 1; printf(&apos;Enter the number of rows: &apos;); scanf(&apos;%d&apos;, &amp;rows); do { int j = 1; do { printf(&apos;%d &apos;, j); j++; } while (j <= i); printf(\'
\'); i++; } while (i<="rows);" return 0; < pre> <p>In this program, we use <strong> <em>nested do...while loops</em> </strong> to generate a pattern of numbers. The <strong> <em>outer loop</em> </strong> controls the number of rows, and the <strong> <em>inner loop</em> </strong> generates the numbers for each row.</p> <p> <strong>Output:</strong> </p> <p>Let us say you input five as the number of rows:</p> <pre> Enter the number of rows: 5 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the program generates a pattern of numbers in a <strong> <em>triangular shape</em> </strong> . The <strong> <em>outer loop</em> </strong> iterates over the rows, and the <strong> <em>inner loop</em> </strong> iterates within each row, printing the numbers from 1 up to the current row number.</p> <h2>Difference between while and do while Loop</h2> <p>Here is a tabular comparison between the while loop and the do-while Loop in C:</p> <table class="table"> <tr> <th>Aspect</th> <th>while loop</th> <th>do-while loop</th> </tr> <tr> <td> <strong>Syntax</strong> </td> <td>while (condition) { ... }</td> <td>do { ... } while (condition);</td> </tr> <tr> <td> <strong>Loop Body Execution</strong> </td> <td>Condition is checked before execution.</td> <td>The body is executed before the condition.</td> </tr> <tr> <td> <strong>First Execution</strong> </td> <td>The condition must be true initially.</td> <td>The body is executed at least once.</td> </tr> <tr> <td> <strong>Loop Execution</strong> </td> <td>May execute zero or more times.</td> <td>Will execute at least once.</td> </tr> <tr> <td> <strong>Example</strong> </td> <td>while (i<5) { printf(\'%d
\', i); i++; }< td> <td>do { printf(&apos;%d
&apos;, i); i++; } while (i<5);< td> </5);<></td></5)></td></tr> <tr> <td> <strong>Common Use Cases</strong> </td> <td>When the loop may not run at all.</td> <td>When you want the loop to run at least once.</td> </tr> </table> <p> <strong>While Loop:</strong> The loop body is executed before the condition is checked. If the condition is initially <strong> <em>false</em> </strong> , the loop may not execute.</p> <p> <strong>Do-while Loop:</strong> The <strong> <em>loop body</em> </strong> is executed at least once before the condition is <strong> <em>checked</em> </strong> . This guarantees that the loop completes at least one iteration.</p> <p>When you want the <strong> <em>loop</em> </strong> to run based on a condition that may be <strong> <em>false</em> </strong> at first, use the <strong> <em>while loop</em> </strong> , and when you want the loop to run at least once regardless of the starting state, use the <strong> <em>do-while loop.</em> </strong> </p> <h2>Features of do while loop</h2> <p>The do-while loop in C has several fundamental characteristics that make it an effective programming technique in certain situations. The following are the significant characteristics of the do-while loop:</p> <ul> <tr><td>Guaranteed Execution:</td> Unlike other <strong> <em>loop structures</em> </strong> , the <strong> <em>do-while oop</em> </strong> ensures that the loop body is executed at least once. Because the condition is assessed after the loop body, the code within the loop is performed before the condition is verified. </tr><tr><td>Loop after testing:</td> The <strong> <em>do-while loop</em> </strong> is a post-tested loop which implies that the loop condition is assessed after the loop body has been executed. If the condition is true, the loop body is run once again. This behavior allows you to verify the condition for repetition before ensuring that a given activity is completed. </tr><tr><td>Conditionally Controlled:</td> The loop continues to execute as long as the condition specified after the while keyword remains <strong> <em>true</em> </strong> . When the condition evaluates to <strong> <em>false</em> </strong> , the loop is terminated, and control shifts to the sentence after the loop. </tr><tr><td>Flexibility:</td> The <strong> <em>do-while loop</em> </strong> may be utilized in several contexts. It is typically used in cases where a piece of code must be executed at least once, such as <strong> <em>menu-driven programs, input validation,</em> </strong> or <strong> <em>repetitive computations</em> </strong> . </tr><tr><td>Nesting Capability:</td> Similar to other <strong> <em>loop constructs</em> </strong> , the <strong> <em>do-while loop</em> </strong> can be <strong> <em>nested</em> </strong> inside other <strong> <em>loops</em> </strong> or <strong> <em>control structures</em> </strong> to create more complex control flow patterns. It allows for the creation of <strong> <em>nested loops</em> </strong> and the implementation of intricate repetitive tasks. </tr><tr><td>Break and Continue:</td> The break statement can be used within a <strong> <em>do-while loop</em> </strong> to terminate the loop execution and exit the loop prematurely. The <strong> <em>continue statement</em> </strong> can skip the remaining code in the current iteration and jump to the next iteration of the loop. </tr><tr><td>Local Scope:</td> Variables declared inside the <strong> <em>do-while loop</em> </strong> body have local scope and are accessible only within the <strong> <em>loop block.</em> </strong> They cannot be accessed outside the loop or by other loops or control structures. </tr><tr><td>Infinite Loop Control:</td> It is crucial to ensure that the loop&apos;s condition is eventually modified within the <strong> <em>loop body</em> </strong> . This modification is necessary to prevent infinite loops where the condition continually evaluates to true. Modifying the condition ensures that the loop terminates at some point. </tr></ul> <hr></=></pre></=></pre></=10);>

דוגמה 3:

ניקח תוכנית שמדפיסה את לוח הכפל של מספר N נתון באמצעות a לעשות... תוך כדי לולאה :

 #include int main() { int N; printf('Enter a number to generate its multiplication table: '); scanf('%d', &N); inti = 1; do { printf('%d x %d = %d
&apos;, N, i, N * i); i++; } while (i<= 10); return 0; } < pre> <p> <strong>Output:</strong> </p> <p>Let us say you enter the number 7 as input:</p> <pre> Please enter a number to generate its multiplication table: 7 7 x 1 = 7 7 x 2 = 14 7 x 3 = 21 7 x 4 = 28 7 x 5 = 35 7 x 6 = 42 7 x 7 = 49 7 x 8 = 56 7 x 9 = 63 7 x 10 = 70 </pre> <p>The program calculates and prints the multiplication table for <strong> <em>7</em> </strong> from 1 to 10.</p> <h3>Infinite do while loop</h3> <p>An <strong> <em>infinite loop</em> </strong> is a loop that runs indefinitely as its condition is always <strong> <em>true</em> </strong> or it lacks a terminating condition. Here is an example of an <strong> <em>infinite do...while loop</em> </strong> in C:</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { inti = 1; do { printf(&apos;Iteration %d
&apos;, i); i++; } while (1); // Condition is always true return 0; } </pre> <p>In this <strong> <em>example</em> </strong> , the <strong> <em>loop</em> </strong> will keep running <strong> <em>indefinitely</em> </strong> because <strong> <em>condition 1</em> </strong> is always <strong> <em>true</em> </strong> .</p> <p> <strong>Output:</strong> </p> <p>When you run the program, you will see that it continues printing <strong> <em>&apos;Iteration x&apos;,</em> </strong> where x is the <strong> <em>iteration number</em> </strong> without stopping:</p> <pre> Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 ... (and so on) </pre> <p>To interrupt an infinite loop like this, you generally use a <strong> <em>break statement</em> </strong> within the <strong> <em>loop</em> </strong> or some external condition you can control, such as <strong> <em>hitting</em> </strong> a specific key combination. In most desktop settings, the keyboard shortcut <strong> <em>Ctrl+C</em> </strong> can escape the Loop.</p> <h3>Nested do while loop in C</h3> <p>In C, we take an example of a <strong> <em>nested do...while loop</em> </strong> . In this example, we will write a program that uses <strong> <em>nested do...while loops</em> </strong> to create a numerical pattern.</p> <p> <strong>Example:</strong> </p> <pre> #include int main() { int rows, i = 1; printf(&apos;Enter the number of rows: &apos;); scanf(&apos;%d&apos;, &amp;rows); do { int j = 1; do { printf(&apos;%d &apos;, j); j++; } while (j <= i); printf(\'
\'); i++; } while (i<="rows);" return 0; < pre> <p>In this program, we use <strong> <em>nested do...while loops</em> </strong> to generate a pattern of numbers. The <strong> <em>outer loop</em> </strong> controls the number of rows, and the <strong> <em>inner loop</em> </strong> generates the numbers for each row.</p> <p> <strong>Output:</strong> </p> <p>Let us say you input five as the number of rows:</p> <pre> Enter the number of rows: 5 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the program generates a pattern of numbers in a <strong> <em>triangular shape</em> </strong> . The <strong> <em>outer loop</em> </strong> iterates over the rows, and the <strong> <em>inner loop</em> </strong> iterates within each row, printing the numbers from 1 up to the current row number.</p> <h2>Difference between while and do while Loop</h2> <p>Here is a tabular comparison between the while loop and the do-while Loop in C:</p> <table class="table"> <tr> <th>Aspect</th> <th>while loop</th> <th>do-while loop</th> </tr> <tr> <td> <strong>Syntax</strong> </td> <td>while (condition) { ... }</td> <td>do { ... } while (condition);</td> </tr> <tr> <td> <strong>Loop Body Execution</strong> </td> <td>Condition is checked before execution.</td> <td>The body is executed before the condition.</td> </tr> <tr> <td> <strong>First Execution</strong> </td> <td>The condition must be true initially.</td> <td>The body is executed at least once.</td> </tr> <tr> <td> <strong>Loop Execution</strong> </td> <td>May execute zero or more times.</td> <td>Will execute at least once.</td> </tr> <tr> <td> <strong>Example</strong> </td> <td>while (i<5) { printf(\'%d
\', i); i++; }< td> <td>do { printf(&apos;%d
&apos;, i); i++; } while (i<5);< td> </5);<></td></5)></td></tr> <tr> <td> <strong>Common Use Cases</strong> </td> <td>When the loop may not run at all.</td> <td>When you want the loop to run at least once.</td> </tr> </table> <p> <strong>While Loop:</strong> The loop body is executed before the condition is checked. If the condition is initially <strong> <em>false</em> </strong> , the loop may not execute.</p> <p> <strong>Do-while Loop:</strong> The <strong> <em>loop body</em> </strong> is executed at least once before the condition is <strong> <em>checked</em> </strong> . This guarantees that the loop completes at least one iteration.</p> <p>When you want the <strong> <em>loop</em> </strong> to run based on a condition that may be <strong> <em>false</em> </strong> at first, use the <strong> <em>while loop</em> </strong> , and when you want the loop to run at least once regardless of the starting state, use the <strong> <em>do-while loop.</em> </strong> </p> <h2>Features of do while loop</h2> <p>The do-while loop in C has several fundamental characteristics that make it an effective programming technique in certain situations. The following are the significant characteristics of the do-while loop:</p> <ul> <tr><td>Guaranteed Execution:</td> Unlike other <strong> <em>loop structures</em> </strong> , the <strong> <em>do-while oop</em> </strong> ensures that the loop body is executed at least once. Because the condition is assessed after the loop body, the code within the loop is performed before the condition is verified. </tr><tr><td>Loop after testing:</td> The <strong> <em>do-while loop</em> </strong> is a post-tested loop which implies that the loop condition is assessed after the loop body has been executed. If the condition is true, the loop body is run once again. This behavior allows you to verify the condition for repetition before ensuring that a given activity is completed. </tr><tr><td>Conditionally Controlled:</td> The loop continues to execute as long as the condition specified after the while keyword remains <strong> <em>true</em> </strong> . When the condition evaluates to <strong> <em>false</em> </strong> , the loop is terminated, and control shifts to the sentence after the loop. </tr><tr><td>Flexibility:</td> The <strong> <em>do-while loop</em> </strong> may be utilized in several contexts. It is typically used in cases where a piece of code must be executed at least once, such as <strong> <em>menu-driven programs, input validation,</em> </strong> or <strong> <em>repetitive computations</em> </strong> . </tr><tr><td>Nesting Capability:</td> Similar to other <strong> <em>loop constructs</em> </strong> , the <strong> <em>do-while loop</em> </strong> can be <strong> <em>nested</em> </strong> inside other <strong> <em>loops</em> </strong> or <strong> <em>control structures</em> </strong> to create more complex control flow patterns. It allows for the creation of <strong> <em>nested loops</em> </strong> and the implementation of intricate repetitive tasks. </tr><tr><td>Break and Continue:</td> The break statement can be used within a <strong> <em>do-while loop</em> </strong> to terminate the loop execution and exit the loop prematurely. The <strong> <em>continue statement</em> </strong> can skip the remaining code in the current iteration and jump to the next iteration of the loop. </tr><tr><td>Local Scope:</td> Variables declared inside the <strong> <em>do-while loop</em> </strong> body have local scope and are accessible only within the <strong> <em>loop block.</em> </strong> They cannot be accessed outside the loop or by other loops or control structures. </tr><tr><td>Infinite Loop Control:</td> It is crucial to ensure that the loop&apos;s condition is eventually modified within the <strong> <em>loop body</em> </strong> . This modification is necessary to prevent infinite loops where the condition continually evaluates to true. Modifying the condition ensures that the loop terminates at some point. </tr></ul> <hr></=></pre></=>

התוכנית מחשבת ומדפיסה את לוח הכפל עבור 7 מ-1 עד 10.

לולאת עשה תוך אינסופית

א לולאה אינסופית הוא לולאה הפועלת ללא הגבלת זמן כפי שמצבה הוא תמיד נָכוֹן או שאין לו תנאי מסיים. הנה דוגמה ל- עשה אינסופי... תוך כדי לולאה ב-C:

דוגמא:

 #include int main() { inti = 1; do { printf('Iteration %d
', i); i++; } while (1); // Condition is always true return 0; } 

בזה דוגמא , ה לוּלָאָה ימשיך לרוץ ללא הגבלת זמן כי תנאי 1 תמיד נָכוֹן .

תְפוּקָה:

כאשר תפעיל את התוכנית, תראה שהיא ממשיכה להדפיס 'איטרציה x', כאשר x הוא ה מספר איטרציה בלי לעצור:

 Iteration 1 Iteration 2 Iteration 3 Iteration 4 Iteration 5 ... (and so on) 

כדי לקטוע לולאה אינסופית כמו זה, אתה בדרך כלל משתמש ב-a הצהרת הפסקה בתוך ה לוּלָאָה או מצב חיצוני כלשהו שאתה יכול לשלוט בו, כגון להכות צירוף מקשים ספציפי. ברוב הגדרות שולחן העבודה, קיצור המקלדת Ctrl+C יכול לברוח מהלולאה.

לולאת עשה תוך כדי קינון ב-C

ב-C, ניקח דוגמה של a מקונן לעשות... תוך כדי לולאה . בדוגמה זו, נכתוב תוכנית המשתמשת מקונן לעשות... תוך כדי לולאות כדי ליצור דפוס מספרי.

דוגמא:

 #include int main() { int rows, i = 1; printf(&apos;Enter the number of rows: &apos;); scanf(&apos;%d&apos;, &amp;rows); do { int j = 1; do { printf(&apos;%d &apos;, j); j++; } while (j <= i); printf(\'
\'); i++; } while (i<="rows);" return 0; < pre> <p>In this program, we use <strong> <em>nested do...while loops</em> </strong> to generate a pattern of numbers. The <strong> <em>outer loop</em> </strong> controls the number of rows, and the <strong> <em>inner loop</em> </strong> generates the numbers for each row.</p> <p> <strong>Output:</strong> </p> <p>Let us say you input five as the number of rows:</p> <pre> Enter the number of rows: 5 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 </pre> <p> <strong>Explanation:</strong> </p> <p>In this example, the program generates a pattern of numbers in a <strong> <em>triangular shape</em> </strong> . The <strong> <em>outer loop</em> </strong> iterates over the rows, and the <strong> <em>inner loop</em> </strong> iterates within each row, printing the numbers from 1 up to the current row number.</p> <h2>Difference between while and do while Loop</h2> <p>Here is a tabular comparison between the while loop and the do-while Loop in C:</p> <table class="table"> <tr> <th>Aspect</th> <th>while loop</th> <th>do-while loop</th> </tr> <tr> <td> <strong>Syntax</strong> </td> <td>while (condition) { ... }</td> <td>do { ... } while (condition);</td> </tr> <tr> <td> <strong>Loop Body Execution</strong> </td> <td>Condition is checked before execution.</td> <td>The body is executed before the condition.</td> </tr> <tr> <td> <strong>First Execution</strong> </td> <td>The condition must be true initially.</td> <td>The body is executed at least once.</td> </tr> <tr> <td> <strong>Loop Execution</strong> </td> <td>May execute zero or more times.</td> <td>Will execute at least once.</td> </tr> <tr> <td> <strong>Example</strong> </td> <td>while (i<5) { printf(\'%d
\', i); i++; }< td> <td>do { printf(&apos;%d
&apos;, i); i++; } while (i<5);< td> </5);<></td></5)></td></tr> <tr> <td> <strong>Common Use Cases</strong> </td> <td>When the loop may not run at all.</td> <td>When you want the loop to run at least once.</td> </tr> </table> <p> <strong>While Loop:</strong> The loop body is executed before the condition is checked. If the condition is initially <strong> <em>false</em> </strong> , the loop may not execute.</p> <p> <strong>Do-while Loop:</strong> The <strong> <em>loop body</em> </strong> is executed at least once before the condition is <strong> <em>checked</em> </strong> . This guarantees that the loop completes at least one iteration.</p> <p>When you want the <strong> <em>loop</em> </strong> to run based on a condition that may be <strong> <em>false</em> </strong> at first, use the <strong> <em>while loop</em> </strong> , and when you want the loop to run at least once regardless of the starting state, use the <strong> <em>do-while loop.</em> </strong> </p> <h2>Features of do while loop</h2> <p>The do-while loop in C has several fundamental characteristics that make it an effective programming technique in certain situations. The following are the significant characteristics of the do-while loop:</p> <ul> <tr><td>Guaranteed Execution:</td> Unlike other <strong> <em>loop structures</em> </strong> , the <strong> <em>do-while oop</em> </strong> ensures that the loop body is executed at least once. Because the condition is assessed after the loop body, the code within the loop is performed before the condition is verified. </tr><tr><td>Loop after testing:</td> The <strong> <em>do-while loop</em> </strong> is a post-tested loop which implies that the loop condition is assessed after the loop body has been executed. If the condition is true, the loop body is run once again. This behavior allows you to verify the condition for repetition before ensuring that a given activity is completed. </tr><tr><td>Conditionally Controlled:</td> The loop continues to execute as long as the condition specified after the while keyword remains <strong> <em>true</em> </strong> . When the condition evaluates to <strong> <em>false</em> </strong> , the loop is terminated, and control shifts to the sentence after the loop. </tr><tr><td>Flexibility:</td> The <strong> <em>do-while loop</em> </strong> may be utilized in several contexts. It is typically used in cases where a piece of code must be executed at least once, such as <strong> <em>menu-driven programs, input validation,</em> </strong> or <strong> <em>repetitive computations</em> </strong> . </tr><tr><td>Nesting Capability:</td> Similar to other <strong> <em>loop constructs</em> </strong> , the <strong> <em>do-while loop</em> </strong> can be <strong> <em>nested</em> </strong> inside other <strong> <em>loops</em> </strong> or <strong> <em>control structures</em> </strong> to create more complex control flow patterns. It allows for the creation of <strong> <em>nested loops</em> </strong> and the implementation of intricate repetitive tasks. </tr><tr><td>Break and Continue:</td> The break statement can be used within a <strong> <em>do-while loop</em> </strong> to terminate the loop execution and exit the loop prematurely. The <strong> <em>continue statement</em> </strong> can skip the remaining code in the current iteration and jump to the next iteration of the loop. </tr><tr><td>Local Scope:</td> Variables declared inside the <strong> <em>do-while loop</em> </strong> body have local scope and are accessible only within the <strong> <em>loop block.</em> </strong> They cannot be accessed outside the loop or by other loops or control structures. </tr><tr><td>Infinite Loop Control:</td> It is crucial to ensure that the loop&apos;s condition is eventually modified within the <strong> <em>loop body</em> </strong> . This modification is necessary to prevent infinite loops where the condition continually evaluates to true. Modifying the condition ensures that the loop terminates at some point. </tr></ul> <hr></=>

הֶסבֵּר:

בדוגמה זו, התוכנית יוצרת דפוס של מספרים ב-a צורה משולשת . ה לולאה חיצונית חוזר על השורות, וה לולאה פנימית חוזר בתוך כל שורה, מדפיס את המספרים מ-1 ועד למספר השורה הנוכחית.

ההבדל בין while ו-do while Loop

הנה השוואה טבלה בין לולאת ה-while ללולאת ה-Do-While ב-C:

תוך כדי לולאה: גוף הלולאה מבוצע לפני בדיקת התנאי. אם המצב הוא בתחילה שֶׁקֶר , ייתכן שהלולאה לא תתבצע.

לולאת עשה תוך כדי: ה גוף לולאה מבוצע לפחות פעם אחת לפני התנאי בָּדוּק . זה מבטיח שהלולאה משלימה איטרציה אחת לפחות.

פרמטר בסקריפט מעטפת

כאשר אתה רוצה את לוּלָאָה לרוץ על סמך תנאי שיכול להיות שֶׁקֶר בהתחלה, השתמש ב- בעוד לולאה , וכאשר אתה רוצה שהלולאה תפעל לפחות פעם אחת ללא קשר למצב ההתחלה, השתמש ב- לולאת עשה תוך כדי.

תכונות של לולאת do while

ללולאת עשה תוך כדי ב-C יש כמה מאפיינים בסיסיים שהופכים אותה לטכניקת תכנות יעילה במצבים מסוימים. להלן המאפיינים המשמעותיים של לולאת ה-Do-While:

ביצוע מובטח:בניגוד לאחרים מבני לולאה , ה עשה-תוך כדי אוף מבטיח שגוף הלולאה מבוצע לפחות פעם אחת. מכיוון שהמצב מוערך לאחר גוף הלולאה, הקוד בתוך הלולאה מבוצע לפני אימות התנאי.לולאה לאחר בדיקה:ה לולאת עשה תוך כדי הוא לולאה שנבדקה לאחר בדיקה אשר מרמזת שמצב הלולאה מוערך לאחר ביצוע גוף הלולאה. אם התנאי נכון, גוף הלולאה מופעל שוב. התנהגות זו מאפשרת לך לאמת את התנאי לחזרה לפני שתוודא שפעילות נתונה הושלמה.בשליטה מותנית:הלולאה ממשיכה לפעול כל עוד נשאר התנאי שצוין לאחר מילת המפתח while נָכוֹן . כאשר המצב מעריך ל שֶׁקֶר , הלולאה מסתיימת, והשליטה עוברת למשפט שאחרי הלולאה.גְמִישׁוּת:ה לולאת עשה תוך כדי ניתן להשתמש בכמה הקשרים. הוא משמש בדרך כלל במקרים שבהם יש לבצע קטע קוד לפחות פעם אחת, כגון תוכניות מונחות תפריט, אימות קלט, אוֹ חישובים חוזרים .יכולת קינון:דומה לאחרים בונות לולאה , ה לולאת עשה תוך כדי יכול להיות מקונן בתוך אחרים לולאות אוֹ מבני בקרה כדי ליצור דפוסי זרימת בקרה מורכבים יותר. זה מאפשר יצירה של לולאות מקוננות ויישום משימות מורכבות שחוזרות על עצמן.הפסקה והמשך:ניתן להשתמש בהצהרת הפסקה בתוך a לולאת עשה תוך כדי כדי להפסיק את ביצוע הלולאה ולצאת מהלולאה בטרם עת. ה להמשיך בהצהרה יכול לדלג על הקוד שנותר באיטרציה הנוכחית ולקפוץ לאיטרציה הבאה של הלולאה.היקף מקומי:משתנים המוצהרים בתוך לולאת עשה תוך כדי לגוף יש היקף מקומי והם נגישים רק בתוך בלוק לולאה. לא ניתן לגשת אליהם מחוץ ללולאה או באמצעות לולאות או מבני בקרה אחרים.בקרת לולאה אינסופית:זה חיוני להבטיח שמצב הלולאה ישתנה בסופו של דבר בתוך גוף לולאה . שינוי זה הכרחי כדי למנוע לולאות אינסופיות שבהן התנאי מוערך ללא הרף. שינוי התנאי מבטיח שהלולאה תסתיים בשלב מסוים.