如何从类函数访问类构造函数变量？

Question

I don't really know how to phrase it so here's an example

class Example() {
    public:
        Example() {
            int variable;
        }

        void Function() {
            // How do you modify variable from here?
        }
}

Answer 1

variable is local to the constructor Example::Example . This means that it cannot be used after it goes out of scope at the closing brace } of the same ctor.

You can instead make variable to be a data member as shown below:

//-----------v------------->removed () from here
class Example {
    public:
//-----------------vvvvvvvv------->use member initializer list to initialize variable
        Example(): variable(0) {
            
        }

        void Function() {
           //use variable as you want
           variable++;   
        }
    private:
        int variable; // variable is a data member now
};

Demo