FindPrime
Define a function that takes an integer argument and returns a logical value true or false depending on if the integer is a prime.
Per Wikipedia, a prime number ( or a prime ) is a natural number greater than 1 that has no positive divisors other than 1 and itself.
Categories:
DO NOT TRY to acquire fancy optimizations first
public static boolean isPrime(int num) {
// single exception
if (num == 2 || num == 5) {
return true;
} else if (num < 2) {
return false;
} // last digit exception
switch (num % 10) {
case 0:
case 2:
case 4:
case 5:
case 6:
case 8:
return false;
} // else
for (int i = 3; i <= Math.sqrt(num); i += 2) {
if (num % i == 0) {
return false;
} } return true;
}