错误＆＃34;调用过载＆＃39; sqrt（int＆amp;）＆＃39;

Question

所以我刚开始用C ++阅读这本书＆＃34; C ++而不用担心第二版＆＃34;我正在做一个让我写这段代码的例子：

#include <iostream>
#include <cmath>
  using namespace std;

int main() {
  int n;
  int i;
  int is_prime = true;

  cout << "Enter a number and press enter: ";
  cin >> n;

  i = 2;
  while (i <= sqrt(n)) {
    if (n % i == 0) {
      is_prime = false;
    }
    i++;
    if (is_prime) {
      cout << "Number is prime" << endl;
    } else {
      cout << "Number is not prime" << endl;
    }
  }
  system("PAUSE");
  return 0;

}

然而，当我尝试编译时，我得到了错误

  

14 C：\ Users \ Owner \ Desktop \ C ++ \ PrimeCheck.cpp   调用重载的`sqrt（int＆amp;）＆＃39;