Example: Fibonacci Sequence Up To N in C

// Fibonacci Sequence Up To N
#include <stdio.h>

int main() {
    // Step 1: Declare variables
    int limit;
    int t1 = 0, t2 = 1; // Initialize first two Fibonacci numbers
    int nextTerm;

    // Step 2: Get user input for the limit
    printf("Enter a positive integer limit: ");
    scanf("%d", &limit);

    // Step 3: Print introductory message
    printf("Fibonacci Sequence up to %d:\n", limit);

    // Step 4: Handle special case for limit 0
    if (limit == 0) {
        printf("0\n");
        return 0; // Exit if limit is 0, only 0 is printed
    }

    // Step 5: Print the first term (0) if within limit
    if (t1 <= limit) {
        printf("%d", t1);
    }

    // Step 6: Print the second term (1) if within limit
    if (t2 <= limit && limit >= 1) { // Also ensure limit is at least 1 to print 1
        printf(", %d", t2);
    }

    // Step 7: Calculate and print subsequent terms
    nextTerm = t1 + t2; // Calculate the third term initially

    while (nextTerm <= limit) {
        printf(", %d", nextTerm); // Print the calculated next term
        t1 = t2;                  // Shift t2 to t1
        t2 = nextTerm;            // Shift nextTerm to t2
        nextTerm = t1 + t2;       // Calculate the new next term
    }

    printf("\n"); // New line for cleaner output

    return 0;
}