Loops in C

In the C programming language, loops are used to execute a block of code repeatedly until a certain condition is met. They are essential for creating efficient and repetitive tasks. This article will provide a comprehensive understanding of loops in C, along with examples to illustrate their usage.

1. The while Loop

The while loop is the simplest type of loop in C. It repeatedly executes a block of code as long as the specified condition is true. The syntax of the while loop is as follows:

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

Here’s an example that prints the numbers from 1 to 5 using a while loop:

#include 

int main()
{
    int i = 1;
    while (i <= 5)
    {
        printf("%d ", i);
        i++;
    }
    return 0;
}

Output:

1 2 3 4 5

2. The do-while Loop

The do-while loop is similar to the while loop, but it guarantees that the code block is executed at least once, even if the condition is false. The syntax of the do-while loop is as follows:

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

Here’s an example that calculates the sum of the numbers from 1 to 10 using a do-while loop:

#include 

int main()
{
    int i = 1;
    int sum = 0;
    do
    {
        sum += i;
        i++;
    } while (i <= 10);
    
    printf("Sum: %d", sum);
    return 0;
}

Output:

Sum: 55

3. The for Loop

The for loop is another commonly used loop in C. It allows for more concise loop initialization, condition, and update in a single line. The syntax of the for loop is as follows:

for (initialization; condition; update)
{
    // code to be executed
}

Here’s an example that prints the even numbers from 1 to 10 using a for loop:

#include 

int main()
{
    for (int i = 2; i <= 10; i += 2)
    {
        printf("%d ", i);
    }
    return 0;
}

Output:

2 4 6 8 10

4. The break Statement

The break statement is used to exit a loop prematurely, regardless of whether the loop condition is true or not. It is often used in conjunction with conditional statements to terminate a loop based on certain conditions. Here’s an example that uses the break statement to exit a loop when the value of i is equal to 5:

#include 

int main()
{
    for (int i = 1; i <= 10; i++)
    {
        if (i == 5)
        {
            break;
        }
        printf("%d ", i);
    }
    return 0;
}

Output:

1 2 3 4

5. The continue Statement

The continue statement is used to skip the current iteration of a loop and proceed to the next iteration. It is often used in conjunction with conditional statements to selectively execute certain parts of the loop. Here’s an example that uses the continue statement to skip the iteration when the value of i is equal to 5:

#include 

int main()
{
    for (int i = 1; i <= 10; i++)
    {
        if (i == 5)
        {
            continue;
        }
        printf("%d ", i);
    }
    return 0;
}

Output:

1 2 3 4 6 7 8 9 10

These are the fundamental loop structures in C. By mastering these loops and understanding their usage, you can effectively control the flow of your program and perform repetitive tasks efficiently. Remember to choose the appropriate loop based on the specific requirements of your program.