While Loop in C

A while loop in C is a control flow statement used to execute a block of code repeatedly as long as a specified condition remains true. It’s a flexible way to iterate over a sequence of values or perform actions until a certain condition is met.

Syntax:

while (condition) {
    // Code to be executed
}

• Condition: An expression that is evaluated before each iteration. If the condition is true, the loop body is executed. If it’s false, the loop terminates.

Example:

int i = 0;
while (i < 5) {
    printf("Hello, world!n");
    i++;
}

In this example:

• i = 0 initializes the loop variable i.
• i < 5 is the condition that checks if i is less than 5.
• The loop body (printf("Hello, world!n")) is executed as long as the condition is true.
• i++ increments i after each iteration.

Common Uses:

• Iterating over arrays or strings.
• Counting or summing values.
• Generating sequences of numbers.
• Reading input from the user until a specific condition is met.

Key Points:

• The while loop is a control flow statement used for iteration.
• The condition is evaluated before each iteration.
• The loop body is executed as long as the condition is true.
• Be careful to avoid infinite loops by ensuring that the condition eventually becomes false.

Example with a User-Defined Condition:

int number;

printf("Enter a positive number: ");
scanf("%d", &number);

while (number <= 0) {
    printf("Please enter a positive number: ");
    scanf("%d", &number);
}

printf("You entered: %dn", number);

This example uses a while loop to prompt the user to enter a positive number until a valid input is provided.