Optimized Approach (Checking Up to √N)
Instead of checking up to num/2, we can optimize by checking up to √num:
c
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#include
#include
int main() {
int num, i, isPrime = 1;
printf("Enter a number: ");
scanf("%d", &num);
if (num <= 1) {
isPrime = 0;
} else {
for (i = 2; i <= sqrt(num); i++) {
if (num % i == 0) {
isPrime = 0;
break;
}
}
}
if (isPrime)
printf("%d is a Prime number.\n", num);
else
printf("%d is not a Prime number.\n", num);https://docs.vultr.com/clang/examples/check-whether-a-number-is-prime-or-not
