assignment-p-01.c

Problem Statement

assignment-p-01.c

Write a C program that includes a user-defined function named isPrime with the signature int isPrime(int num); The function should take an integer as a parameter and return 1 if the number is prime and 0 otherwise.

Source Code

#include <stdio.h>
#include <math.h>

int isPrime(int);

int main()
{
    int n;
    printf("Enter the number: ");
    scanf("%d", &n);

    if (isPrime(n))
    {
        printf("\nInput %d is a Prime Number.", n);
    }
    else
    {
        printf("\nInput %d is not a Prime Number.", n);
    }

    return 0;
}

int isPrime(int n)
{
    if (n <= 1)
        return 0;
    if (n == 2)
        return 1;
    if (n % 2 == 0)
        return 0;

    int temp = (int)sqrt(n);
    int i;
    for (i = 3; i <= temp; i += 2)
    {
        if (n % i == 0)
        {
            return 0;
        }
    }
    return 1;
}

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● Author - Amit Dutta · Updated - 12 Dec 2025