A number is classified as a prime if it is greater than one and is divisible only by one and by itself. Only natural numbers are classified as prime. Before knowing more about the prime number, it is important to remember some rules of divisibility, which help in the identification of which numbers are not prime.
Code:
#include <stdio.h>
int prime_number(int, int);
int main()
{
int num, tmp;
printf("Input any integer number: ");
scanf("%d", &num);
tmp = prime_number(num, num / 2);
if (tmp == 1)
{
printf("%d is a prime number\\", num);
}
else
{
printf("%d is not a prime number\\", num);
}
return 0;
}
int prime_number(int num, int i)
{
if (i == 1)
{
return 1;
}
else
{
if (num % i == 0)
{
return 0;
}
else
{
return prime_number(num, i - 1);
}
}
}