getting conversion error between int and char

[LemonHappy]

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

class Square {

private:
double side;


public:

double getArea() {
return side * side;
}

void setSide(double s) {
side = s;
}




// Overload + operator to add two Square objects.
Square operator+(const Square& b) {
Square square;
square.side = side + b.side;
return square;
}

Square operator-(const Square& b) {
Square square;
square.side = side - b.side;
return square;
}


Square operator*(const Square& b) {
Square square;
square.side = side * b.side;
return square;

}

Square operator/(const Square& b) {
Square square;
square.side = side / b.side;
return square;
}
};

// Main function
int main() {
Square Square1;
Square Square2;
Square Square3;

double area = 0.0;


Square1.setSide(2.0);

Square2.setSide(5.0);


// Square1 area
area = Square1.getArea();
cout << "Area of Square1 : " << area << endl;

// Square2 area
area = Square2.getArea();

cout << "Area of Square2 : " << area << endl;

char op;

cout << "Enter the operator: ";
cin >> op;
switch (op)
{
case '+':
Square3 = Square1 + Square2;
cout << Square3;
break;
case '-':
Square3 = Square1 - Square2;
cout << Square3;
break;
case '*':
Square3 = Square1 * Square2;
cout << Square3;
break;
default:
cout << "No a valid operator";
}
return 0;
}

[kiseitai2]

Where is the error? Is it at compile time, linking time, or runtime? Please, post the error output!

[LemonHappy]

cannot bind 'std::ostream {aka std::basic_ostream<char>}' lvalue to 'std::basic_ostream<char>&&'

It's the error where "cout << Square3;" It's ether a definition or conversion error, because it tell me there's no operator for <<

[weaknessforcats]

A Square is a class. When you code:

cout << Square3;

you are really coding:

ostream& operator<<(ostream& os, Square& arg);

and the compiler can't find this function. You will need to write this as a friend function to class Square so the function can access the private members of Square.

Or, you write member functions to Square to fetch the data:

cout << Square3.GetSide() << endl;

where

double Square::GetSide()
{
 return side;
}

That will return a double and the compiler knows how to cout a double.