如何编写一个函数来打印出c中素数的平均值

Question

I'm trying to solve a problem, where I am supposed to write a function that prints out the mean value of all prime numbers between 2 and N but I don't know how to start. I have already written a function that prints out all the prime numbers.

Answer 1

1. sum the prime numbers as you find them instead of printing
2. also count the number of primes you found
3. then divide the sum by number of primes

for example, assuming you have written the function for prime :

 count=0;
 for(i=2;i<n;i++) {
        if(isPrime(i)) {
            sum+=i;
            count++;
        }
    }
 mean = sum/count; // watch for integer division