Define a function that returns the number of prime in range in processing language

Question

Define a function that when passed an integer (n), returns the number of primes in the range [1, n]. For example,

if n = 5, return 3, since the numbers 2, 3 and 5 are primes.

if n = -5, return 0.

if n = 10, return 4, since the numbers 2, 3, 5, and 7 are primes. Question need to be using processing.

    boolean isPrime(int n) {
    if(n < 2) {
        return false;
    }
    for(int i=2; i*i<=n; i++) {
        if(n%i==0) {
            return false;
        }
    }
    return true;
    }

Answer 1

    int countPrimes(int n) {
        if(n <= 2){
            return 0;
        } else if(n == 3){
            return 1;
        }
        int count = 0;
        for(int i = 2; i <= n; i++){
            if(IsPrime( i )){
                count++;
            }
        }
        return count;
    }
    boolean IsPrime(int num) {
        for(int i=2;i<=num/2;i++){
            if(num % i == 0){
                return false;
            }
        }
        return true;
    }
}