Overload ++ operator

Question

I am trying to deal with operator overloading at the first time, and I wrote this code to overload ++ operator to increment class variables i and x by one.. It does the job but the compiler showed these warnings:

Warning 1 warning C4620: no postfix form of 'operator ++' found for type 'tclass', using prefix form c:\users\ahmed\desktop\cppq\cppq\cppq.cpp 25

Warning 2 warning C4620: no postfix form of 'operator ++' found for type 'tclass', using prefix form c:\users\ahmed\desktop\cppq\cppq\cppq.cpp 26

This is my code:

class tclass{
public:
    int i,x;
    tclass(int dd,int d){
        i=dd;
        x=d;
    }
    tclass operator++(){

        i++;
        x++;
        return *this;

    }
};

int main() {
    tclass rr(3,3);
    rr++;
    rr++;
    cout<<rr.x<<" "<<rr.i<<endl;
    system("pause");
    return 0;
}

Answer 1

This syntax:

tclass operator++()

is for prefix ++ (which is actually normally written as tclass &operator++()). To distinguish the postfix increment, you add a not-used int argument:

tclass operator++(int)

Also, note that the prefix increment better return tclass & because the result may be used after: (++rr).x.

Again, note that the postfix increment looks like this:

tclass operator++(int)
{
    tclass temp = *this;
    ++*this;     // calls prefix operator ++
                 // or alternatively ::operator++(); it ++*this weirds you out!!
    return temp;
}

Answer 2

There are two ++ operators. You defined one and used the other.

tclass& operator++(); //prototype for    ++r;
tclass operator++(int); //prototype for  r++;