#### Check Prime

```/**
*
* @file
* A simple program to check if the given number if prime or not.
*
* @brief
* Reduced all possibilities of a number which cannot be prime.
* Eg: No even number, except 2 can be a prime number, hence we will increment
* our loop with i+6 jumping and check for i or i+2 to be a factor of the
* number; if it's a factor then we will return false otherwise true after the
* loop terminates at the terminating condition which is (i*i<=num)
*/

#include <cassert>   /// for assert
#include <iostream>  /// for IO operations

/**
* Function to check if the given number is prime or not.
* @param num number to be checked.
* @return if number is prime, it returns @ true, else it returns @ false.
*/
template <typename T>
bool is_prime(T num) {
bool result = true;
if (num <= 1) {
return false;
} else if (num == 2 || num == 3) {
return true;
} else if ((num % 2) == 0 || num % 3 == 0) {
return false;
} else {
for (T i = 5; (i * i) <= (num); i = (i + 6)) {
if ((num % i) == 0 || (num % (i + 2) == 0)) {
result = false;
break;
}
}
}
return (result);
}

/**
* Main function
*/
int main() {
// perform self-test
assert(is_prime(50) == false);
assert(is_prime(115249) == true);

int num = 0;
std::cout << "Enter the number to check if it is prime or not" << std::endl;
std::cin >> num;
bool result = is_prime(num);
if (result) {
std::cout << num << " is a prime number" << std::endl;
} else {
std::cout << num << " is not a prime number" << std::endl;
}

return 0;
}
```  