## Algorithm

Prime Number has some following conditions to become a Full prime number. Prime Number Cases when it will be fullfilled the requirement of prime number:

1. Prime number should be a whole number
2. Prime number should be greater than 1
3. Prime number should have only 2 factors. The factors are 1 and the number itself.

Examples of Prime Numbers : 2, 3, 5, 7, 11, 13, 17, 19, 23 etc.
Examples of non-Prime Numbers : 4, 6, 8, 9, 10, 12, 14, 15, 16

## Code Examples

### #1 Prime Number Checker Using C Programming

```Code - C Programming```

``````#include <stdio.h>

int main() {
int n, i, flag = 0;
printf("Enter a positive integer: ");
scanf("%d", &n);

for (i = 2; i <= n / 2; ++i) {
if (n % i == 0) { // Check a non-prime number
flag = 1;
break;
}
}

if (n == 1) {
printf("1 is neither prime nor composite.");
}
else {
if (flag == 0)
printf("%d is a prime number.", n);
else
printf("%d is not a prime number.", n);
}

return 0;
}``````
Copy The Code &

Input

cmd
Enter a positive integer: 2

Output

cmd
2 is a prime number.

### #2 Prime Number or Composite number Check using C Programming

```Code - C Programming```

``````#include <stdio.h>

int main()
{
int n, c;

printf("Enter a number to check if it's prime\n");
scanf("%d", &n);

for (c = 2; c <= n / 2; c++)
{
if (n % c == 0)
{
printf("%d is a composite number.\n", n);
break;
}
}

if (c == n / 2 + 1)
printf("%d is a prime number.\n", n);

return 0;
}``````
Copy The Code &

Input

cmd
Enter a number to check if it's prime: 9

Output

cmd
9 is a composite number.

### #3 Prime Number solution Using Function C Programming

```Code - C Programming```

``````#include <stdio.h>
int check_prime(int);

int main()
{
int n, result;

printf("Enter an integer to check whether it's prime or not.\n");
scanf("%d",&n);

result = check_prime(n);

if (result == 1)
printf("%d is a prime number.\n", n);
else
printf("%d is not a prime.\n", n);

return 0;
}

int check_prime(int a)
{
int c;

for (c = 2; c <= a - 1; c++)
{
if (a%c == 0)
return 0;
}
if (c == a)
return 1;
}``````
Copy The Code &

Input

cmd
2

Output

cmd
2 is a prime number.