for Loop (for Statement) in C Programming Language

The for loop in the C programming language is a control structure that allows you to repeat a block of code a specific number of times. It consists of an initialization expression, a loop condition, and an update expression. This tutorial will explain how to use the for loop in C, including its syntax, a simple example, and common use cases.

For loop syntax

The for loop in C has the following syntax:

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

initialization: This is an expression that initializes the loop variable(s). It is executed only once when the loop starts.
condition: This is a test condition that is checked before each iteration of the loop. If the condition is true, the loop body will be executed. If it is false, the loop will exit.
update: This expression is executed after each iteration of the loop body. It typically updates the loop variable(s) to prepare for the next iteration.

Simple for loop example

Here is a simple example of a for loop that prints the numbers from 1 to 10:

#include <stdio.h>

int main() {
    for (int i = 1; i <= 10; i++) {
        printf("%d\n", i);
    }

    return 0;
}

In this example, the loop variable i is initialized to 1, the condition checks whether i is less than or equal to 10, and the update expression increments i by 1 after each iteration. The loop body simply prints the value of i.

Common use cases for the for loop

The for loop is often used for:

Iterating over arrays or other data structures
Performing a specific number of iterations
Repeating a block of code until a condition is met

Here's an example of a for loop iterating over an array:

#include <stdio.h>

int main() {
    int arr[] = {10, 20, 30, 40, 50};
    int length = sizeof(arr) / sizeof(arr[0]);

    for (int i = 0; i < length; i++) {
        printf("arr[%d] = %d\n", i, arr[i]);
    }

    return 0;
}

In this example, the for loop iterates over each element of the array arr and prints its index and value.

In summary, the for loop in C is a control structure that allows you to repeat a block of code a specific number of times. It consists of an initialization expression, a loop condition, and an update expression. The for loop is commonly used for iterating over arrays or other data structures, performing a specific number of iterations, and repeating a block of code until a condition is met.

Using For Loops for Iteration in C Language:

#include <stdio.h>

int main() {
    // Using for loop for iteration
    for (int i = 1; i <= 5; ++i) {
        printf("Iteration %d\n", i);
    }

    return 0;
}

C Code Examples with For Loop:

#include <stdio.h>

int main() {
    // For loop example
    for (int i = 0; i < 5; ++i) {
        printf("%d ", i);
    }

    return 0;
}

Nested For Loops in C Programming:

#include <stdio.h>

int main() {
    // Nested for loops example
    for (int i = 1; i <= 3; ++i) {
        for (int j = 1; j <= 3; ++j) {
            printf("(%d, %d) ", i, j);
        }
        printf("\n");
    }

    return 0;
}

Controlling Loop Execution with Break and Continue in C:

#include <stdio.h>

int main() {
    // Using break and continue in for loop
    for (int i = 1; i <= 5; ++i) {
        if (i == 3) {
            break;  // Exit the loop when i is 3
        }

        if (i == 2) {
            continue;  // Skip the rest of the loop and go to the next iteration when i is 2
        }

        printf("Iteration %d\n", i);
    }

    return 0;
}

Looping Through Arrays with For in C:

#include <stdio.h>

int main() {
    // Looping through an array with for loop
    int numbers[] = {1, 2, 3, 4, 5};

    for (int i = 0; i < 5; ++i) {
        printf("%d ", numbers[i]);
    }

    return 0;
}

Common Mistakes and Pitfalls with the For Loop in C:

#include <stdio.h>

int main() {
    // Common mistake: forgetting to increment the loop variable
    for (int i = 0; i < 5; /* missing increment */) {
        printf("%d ", i);
    }

    return 0;
}