Break and Continue

The break statement terminates a loop, and continue skips the rest of the code in the loop.

Break Statement

The break statement is used to terminate a loop. It stops the execution of the loop and transfers the control to the next statement following the loop.

• Usage of break
  • Exiting Loops:
    • The break statement terminates the closest enclosing for, while, or do-while loop.
  • Switch Case:
    • It exits a switch block to prevent the execution of the next case(s).

#include <stdio.h>
int main() {
    for (int i = 0; i < 5; i++) {
        if (i == 3) 
        break;
        printf("%d\n", i);
    }
    printf("Loop exited.\n");
    return 0;
}

#include <stdio.h>
int main() {
    while (i <= 10) {
        if (i == 5) {
            break;  // Exit the loop when i is 5
        }
        printf("%d\n", i);
        i++;
    }
    printf("Loop exited.\n");
    return 0;
}

#include <stdio.h>
int main() {
    int i = 1;
    do {
        if (i == 5) {
            break;  // Exit the loop when i is 5
        }
        printf("%d\n", i);
        i++;
    } while (i <= 10);
    printf("Loop exited.\n");
    return 0;
}

#include <stdio.h>
int main() {
    int choice;
    printf("Enter a number (1-3): ");
    scanf("%d", &choice);
    switch (choice) {
        case 1:
            printf("Option 1 selected.\n");
            break;  // Exit the switch block
        case 2:
            printf("Option 2 selected.\n");
            break;
        case 3:
            printf("Option 3 selected.\n");
            break;
        default:
            printf("Invalid option.\n");
    }

    return 0;
}

• Key Points
  • Immediate Exit:
    • The break statement exits the nearest enclosing loop or switch.
  • Placement:
    • Use break carefully in nested loops or multiple switch statements to ensure the correct block is exited.
  • Avoid Infinite Loops:
    • Combine break with conditional checks to ensure that the program doesn't get stuck in an infinite loop.
  • Control Flow:
    • Improves control over the flow of loops or cases but can make code harder to follow if overused.

Continue Statement

The continue statement in C is used to skip the rest of the code in the current iteration of a loop and proceed directly to the next iteration. It is typically used to bypass certain parts of the loop when a specific condition is met, without terminating the loop.

• Usage of continue
  • For Loop:
    • Skips the remaining statements in the current iteration and jumps to the next iteration by executing the increment/decrement operation.
  • While/Do-While Loop:
    • Skips the rest of the current iteration and evaluates the loop condition to decide if the next iteration should run.

#include <stdio.h>
int main() {
    for (int i = 0; i < 5; i++) {
        if (i == 2) 
        continue;  // Skips the itereation when i is 2
        printf("%d\n", i);
    }
    return 0;
}

#include <stdio.h>
int main() {
    int i = 1;
    while (i <= 5) {
        if (i == 3) {
            i++;  // Increment before continue to avoid infinite loop
            continue;  // Skip the iteration when i is 3
        }
        printf("%d\n", i);
        i++;
    }
    return 0;
}

#include <stdio.h>
int main() {
    int i = 1;
    do {
        if (i == 3) {
            i++;  // Increment before continue to avoid infinite loop
            continue;  // Skip the iteration when i is 3
        }
        printf("%d\n", i);
        i++;
    } while (i <= 5);
    return 0;
}

• Key Points
  • Skip Code Execution:
    • continue skips the remaining code in the loop body for the current iteration.
  • Placement:
    • Always ensure proper increments or updates are made before continue to prevent infinite loops.
  • Control Flow:
    • Allows fine-grained control over loop behavior, but excessive use can make code harder to read.
  • Difference from break:
    • continue skips to the next iteration, while break exits the loop entirely.