Count composite numbers in a range (for loop) Dry Run in C

Count composite numbers in a range (for loop) is an interactive C dry run visualizer from the Nested programs section. Study the source code, then use the execution controls to follow each step, variable update, highlighted line, and console output.

This page provides a browser-based dry run with source-code highlighting, auto-scroll, voice narration controls, and execution output for learning the program step by step.

Count composite numbers in a range (for loop) Program Code

#include <stdio.h>
int main() {
    int start, end, composite_count = 0, num, i;
    printf("Enter range (start end): ");
    scanf("%d %d", &start, &end);
    
    for(num = start; num <= end; num++) {
        if(num < 4) continue;  // Smallest composite is 4
        
        int isComposite = 0;
        for(i = 2; i < num; i++) {
            if(num % i == 0) {
                isComposite = 1;
                break;
            }
        }
        if(isComposite) composite_count++;
    }
    
    printf("Composite numbers from %d to %d: %d\n", start, end, composite_count);
    return 0;
}

View the complete Nested programs page.