pc-ip-04.c

Problem Statement

pc-ip-04.c

Question 4: Write a function to check whether a number is prime or not. Use the same function to generate all prime numbers less than 100.

Source Code

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

int isPrime(int);

int main()
{
    int n, i;
    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);
    }
    printf("\nPrime numbers from 1 to 100:");
    for (i = 1; i <= 100; i++)
    {
        if (isPrime(i))
        {
            printf("  %d", i);
        }
    }
    return 0;
}

int isPrime(int n)
{
    int i;
    int end = (int)sqrt(n);
    if (n == 0 || n == 1)
    {
        return 0;
    }
    for (i = 2; i <= end; i++)
    {
        if (n % i == 0)
        {
            return 0;
        }
    }
    return 1;
}

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● Author - Amit Dutta · Updated - 05 Jan 2026