NBC 103 • Practical #4

Fibonacci Sequence & Prime Number Checker

Aim: To generate N terms of the Fibonacci sequence and determine if a number is Prime using loop constructs.

Step-by-Step Algorithm & Logic

  • 11. For Fibonacci: Initialize t1 = 0, t2 = 1. In a loop up to N, print t1, next = t1 + t2, t1 = t2, t2 = next.
  • 22. For Prime: Assume isPrime = true for num > 1. Loop from i = 2 up to sqrt(num).
  • 33. If (num % i == 0), set isPrime = false and break.
  • 44. Display whether number is Prime or Composite.

Complete Tested Source Code

#include <stdio.h>
#include <stdbool.h>

int main(void) {
    int n = 8, num = 29;
    long long t1 = 0, t2 = 1, next;

    printf("=== Fibonacci Sequence (%d terms) ===\n", n);
    for (int i = 1; i <= n; i++) {
        printf("%lld ", t1);
        next = t1 + t2;
        t1 = t2;
        t2 = next;
    }
    printf("\n\n");

    printf("=== Prime Number Checker ===\n");
    bool isPrime = (num > 1);
    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0) {
            isPrime = false;
            break;
        }
    }

    if (isPrime)
        printf("%d is a PRIME number.\n", num);
    else
        printf("%d is NOT a prime number.\n", num);

    return 0;
}

Sample Input:

n = 8, num = 29

Sample Output:

Fibonacci: 0 1 1 2 3 5 8 13
29 is a PRIME number.

Practical Exam Viva Questions (Exp #4)

1 Questions
1

Why do we test loop condition i * i <= num instead of i < num?