Operator Overloading in C++

cpp--binary-operator-overloading.cpp

#include <iostream>
using namespace std;

class Complex{
    private:
        int real, imag;
    public:
        Complex(){
            real = 0;
            imag = 0;
        }
        Complex(int r, int i){
            real = r;
            imag = i;
        }
        
        void print(){
            cout << "Complex number is: " << real << " + " << imag << "i" << endl; 
        }
        
        Complex operator +(Complex c){
            Complex temp;
            temp.real = real+c.real;
            temp.imag = imag+c.imag;
            return temp;
        }
};

int main()
{
    Complex c(1,2);
    Complex c1(2,5);
    Complex c2;
    
    c.print();
    c2 = c+c1;
    
    c2.print();
    return 0;
}

cpp-string-concatenation-operator-overloading.cpp

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

class String{
  private:
    char str[4];

  public:
    void getString(){
      cout << "Enter the string: "; cin >> str;
    }

    void print(){
      cout << "String is: " << str << endl;
    }

    String operator +(String s){
      String temp;
      strcpy(temp.str, str);
      strcat(temp.str, s.str);
      return temp;
    }
};

int main(){ 
  String s, s1, s2;
  s.getString();
  s1.getString();
  s2 = s + s1;
  s2.print();
  return 0;
}

cpp-unary-operator-overloading.cpp

#include <iostream>
using namespace std;

class Counter{
    private:
        int count;
    public:
        Counter(){
            count = 0;
        }
        
        void print(){
            cout << "Count: " << count << endl;
        }
        
        Counter operator ++(){
            Counter temp;
            temp.count = ++count;
            return temp;
        }
        
        Counter operator ++(int){
            Counter temp;
            temp.count = count++;
            return temp;
        }
};

int main(){
    
    Counter c;
    Counter c1;
    
    // ++c;
    // c++;
    // c.print();
    
    c1 = ++c;
    //c1 = c++;
    c1.print();
    return 0;
}