Example: Fibonacci Series (Iterative) in C

C
C++
C#
Java
Python
PHP
// Fibonacci Series (Iterative)
#include <stdio.h>

int main() {
    int n, i;
    int t1 = 0, t2 = 1;
    int nextTerm;

    // Step 1: Prompt user for the number of terms
    printf("Enter the number of terms: ");
    scanf("%d", &n);

    printf("Fibonacci Series: ");

    // Step 2: Handle edge cases for n = 1 or n = 2
    if (n <= 0) {
        printf("Please enter a positive integer.\n");
    } else if (n == 1) {
        printf("%d\n", t1);
    } else {
        // Step 3: Iterate and print the series
        // Print the first two terms outside the loop
        printf("%d, %d", t1, t2);

        // Calculate and print subsequent terms
        for (i = 3; i <= n; ++i) {
            nextTerm = t1 + t2;
            printf(", %d", nextTerm);
            t1 = t2;
            t2 = nextTerm;
        }
        printf("\n");
    }

    return 0;
}