Reduce values ​of a variable that is defined with the value of a function

Question

I'm looking for a way to reduce the value of a variable that takes its value from a function. However, until now I haven't thought of anything.

The way it is written, the code currently will always return the value of the function.

std::string Barger::ShowMessage() {

    int var = Barger::get().var();

    char mes[20];

    sprintf_s(mes, sizeof(mes), "Value Var %d", var--);

    return std::string(mes);
}

What I need is that every time the std::string Barger::ShowMessage() function is executed it will be reduced by -1 from the variable, but the function Barger::get().var() is not allowing this.

Answer 1

You are not saving the result of operator-- anywhere other than in a local variable, so every time you call ShowMessage(), you are retrieving the same original value again and again. You need something more like the following, which you will have to add if you do not already have it:

std::string Barger::ShowMessage() {

    int var = Barger::get().var();

    char mes[20];

    sprintf_s(mes, sizeof(mes), "Value Var %d", var--);

    Barger::get().setvar(var); // <-- here

    return std::string(mes);
}

Unless you can change var() to return a non-const int& reference to some internal int variable, rather than returning an int copy of it:

std::string Barger::ShowMessage() {

    int& var = Barger::get().var();

    char mes[20];

    sprintf_s(mes, sizeof(mes), "Value Var %d", var--);

    return std::string(mes);
}