Why do we use this keyword in operator overloading?

Question

So I'm a beginner c++ programmer and when I read the sololearn tutorial, it said this keyword is important in operator overloading. I don't know why we use this keyword. I tried without using this keyword and got the output I expected.

Answer 1

#include <iostream>
using namespace std;
class MyClass {
public:
int var;
MyClass() {}
MyClass(int a)
: var(a) { }

MyClass operator+(MyClass &obj) { // here obj has the value of obj2.
MyClass res;
res.var= this->var+obj.var; // as the passed argument can access its variable var directly, so obj.var has the value of obj2

// but how will you access obj1 value for that "this" keyword is being used here.
// so res.var will contain obj1+obj2.
return res;
}
};
int main(){
MyClass obj1(123),obj2(145);
MyClass result= obj1+obj2; // here result also has. its own var variable
// obj1+obj2 will be pronounced as obj1 called + operator and passed obj2 as an argument.
cout<<result.var;
return 0;
}