"Why is too many parameters prompted without adding friend"

1 # include <iostream> 2 using namespace STD; 3 4 class complex 5 {6 double real, imag; 7 public: 8 complex (Double R, double I ): real (R), imag (I) {} 9 complex operator + (Double R); 10 complex operator + (Double R, const complex & C); // change it to the following: friend complex operator + (Double R, const complex & C) 11 void valueget () {12 cout <real <"," <imag <Endl; 13} 14}; 15 complex: Operator + (double r) 16 {17 return complex (Real + R, IMAG); 18} 19 20 int main () 21 {22 complex C1 (3, 2); 23 C1 = C1 + 3; 24 c1.valueget (); 25}

The above program compiler will report an error. The error is

Error 1 error c2804: Binary 'operator + 'hasToo parameter Parameters

The reason is that when the operator is overloaded, it can be reloaded as a member function or a common function.

When the overload is a common function, the number of parameters should be the number of operators.

When the overload is a member function, the number of parameters should be equal to the number of operators minus one.

For the "+" to be overloaded here, the number of operators is 2. If the overload is a common function, the number of parameters should be 2. If the reload is a member function, the number of parameters should be 1.

This corresponds to the addition of friend. When friend is added, it indicates that although this function is inside the class, it is a common function rather than a member function. The parameter must be 2. Without friend, this is a member function of the class. The parameter should be set to one.

 

"Why is too many parameters prompted without adding friend"