CodeToLive

Control Structures in C

Control structures in C allow you to control the flow of your program. They include conditional statements (if-else, switch) and loops (for, while, do-while).

If-Else Statements

The if-else statement is used to execute a block of code based on a condition. You can also use else if to check multiple conditions.

#include <stdio.h>

int main() {
    int age = 20;
    if (age >= 18) {
        printf("You are an adult.\n");
    } else if (age >= 13) {
        printf("You are a teenager.\n");
    } else {
        printf("You are a child.\n");
    }
    return 0;
}
      

Nested If-Else

You can nest if-else statements to check conditions within conditions.

#include <stdio.h>

int main() {
    int age = 20;
    char gender = 'M';
    if (age >= 18) {
        if (gender == 'M') {
            printf("You are an adult male.\n");
        } else {
            printf("You are an adult female.\n");
        }
    } else {
        printf("You are a minor.\n");
    }
    return 0;
}
      

Switch Statement

The switch statement is used to execute one of many code blocks based on the value of an expression. It is often used as an alternative to multiple if-else statements.

#include <stdio.h>

int main() {
    int day = 3;
    switch (day) {
        case 1:
            printf("Monday\n");
            break;
        case 2:
            printf("Tuesday\n");
            break;
        case 3:
            printf("Wednesday\n");
            break;
        default:
            printf("Invalid day\n");
    }
    return 0;
}
      

Loops

Loops are used to execute a block of code repeatedly. C supports for, while, and do-while loops.

For Loop

The for loop is used when you know how many times you want to execute a block of code.

#include <stdio.h>

int main() {
    for (int i = 0; i < 5; i++) {
        printf("%d\n", i);
    }
    return 0;
}
      

While Loop

The while loop is used when you want to repeat a block of code as long as a condition is true.

#include <stdio.h>

int main() {
    int count = 0;
    while (count < 5) {
        printf("%d\n", count);
        count++;
    }
    return 0;
}
      

Do-While Loop

The do-while loop is similar to the while loop, but it guarantees that the block of code is executed at least once.

#include <stdio.h>

int main() {
    int count = 0;
    do {
        printf("%d\n", count);
        count++;
    } while (count < 5);
    return 0;
}
      

Break and Continue

The break statement is used to exit a loop or a switch statement prematurely. The continue statement is used to skip the rest of the loop and proceed to the next iteration.

#include <stdio.h>

int main() {
    for (int i = 0; i < 10; i++) {
        if (i == 5) {
            break; // Exit the loop when i is 5
        }
        if (i % 2 == 0) {
            continue; // Skip even numbers
        }
        printf("%d\n", i);
    }
    return 0;
}
      

Nested Loops

You can nest loops within loops to create more complex control structures.

#include <stdio.h>

int main() {
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            printf("i = %d, j = %d\n", i, j);
        }
    }
    return 0;
}