C Program to Check Whether a Number is Prime or Not

https://docs.vultr.com/clang/examples/check-whether-a-number-is-prime-or-not

C Program to Check Whether a Number is Prime or Not

A prime number is a number greater than 1 that has only two factors: 1 and itself (e.g., 2, 3, 5, 7, 11).

C Program to Check Prime Number

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#include

int main() {

    int num, i, isPrime = 1; // Assume the number is prime (isPrime = 1)

    // Input from user

    printf("Enter a number: ");

    scanf("%d", &num);

    // Prime numbers must be greater than 1

    if (num <= 1) {

        isPrime = 0;

    } else {

        // Check divisibility from 2 to num/2

        for (i = 2; i <= num / 2; i++) {

            if (num % i == 0) {

                isPrime = 0; // If divisible, it's not prime

                break;

            }