Syntax for the do-while Loop in C programming

Syntax for the do-while Loop in C

The do-while loop in C is a control flow statement that executes a block of code at least once and then repeatedly executes the block as long as a specified condition is true. The key feature of the do-while loop is that it checks the condition after executing the code block, ensuring that the code runs at least once.

Basic Syntax

The syntax for a do-while loop is as follows:

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

In this syntax:

• do begins the loop.
• The block of code within curly braces { } is executed once before the condition is checked.
• The while (condition) checks the condition after the code block has been executed.
• If the condition evaluates to true, the loop repeats; if false, the loop terminates.

Example Code

Here’s an example demonstrating how to use a do-while loop:

#include <stdio.h>

int main() {
    int i = 0;

    do {
        printf("%d\n", i);
        i++;
    } while (i < 5);

    return 0;
}

In this example:

• The do-while loop starts with i initialized to 0.
• The loop prints the current value of i and then increments i by 1.
• After executing the code block, the condition i < 5 is checked.
• The loop continues until i is no longer less than 5, at which point the loop exits.

Key Points

• Guaranteed Execution: The do-while loop guarantees that the code block executes at least once, regardless of the initial condition.
• Condition Checking: The condition is checked after the loop body execution. If the condition is true, the loop executes again.
• Use Cases: Ideal for scenarios where you need the loop to run at least once before evaluating the condition, such as menu-driven programs or user input validation.

Note: The do-while loop is particularly useful when the initial iteration must occur before the condition is evaluated, ensuring that the code runs at least once.