/*
Author Yana
This program checks whether input number is prime or not. Version 1.
Input: A positive integer n>=2.
Output: A message whether n is prime or not.
Algorithm:
1. Read input number
2. Check and count all possible divisors from 1 up to n.
3. n is prime if it is has exactly two different divisors - 1 and itself.
Assumption: input valid.
*/
#include<stdio.h >
int main(){
- int n;        /* Input number. */
- int divisor;     /* Possible divisor tested. */
- int counter = 0;     /* Number of divisors found. */
- /* Read input */
- printf( "Please enter a number ");
- scanf("%d", &n);
- /* Check and count all possible divisors. */
- for (divisor = 1; divisor <= n; divisor ++){
- }
- /* Print output */
- if (counter == 2)
- printf("The number %d is a prime number \n", n);
- else
- printf("The number %d is not a prime number\n", n);
- return 0;
}