c++ - 'more than one instance of overloaded function "sqrt“匹配参数列表”怎么办？

Question

我的代码在 for 循环中出错，for ( j = 3; j <=sqrt(num); j +=2) :

more than one instance of overloaded function "sqrt" matches the argument list.

我该如何解决？

# include <cmath>

// determine if number is prime
bool isPrime (long n) 
{
  int j, num = 0;
  {
    if (num <=1)
      return false;
  }
  for ( j = 3; j <=sqrt(num); j +=2)
  {
    if (num % j == 0)
      return false;
  }   
  return true;
}

Answer 1

尝试:

for (j = 3; j <= std::sqrt(static_cast<float>(num)); j +=2)

发生的事情是<cmath>包含 3 个不同的 definitions of sqrt并且编译器不知道您要使用哪个。