C++ cin within funtions?

Question

void test(int a){

cin >> a;

}

int main () {

int number;

test(number);

cout << number;

return 0;

}

Why dosen't number take on the value of a? What other ways can I get user input within a funtion?

Thanks =)

? · Accepted Answer

Because a was passed to test() by value. Changes made to test()'s a have no effect on main()'s numer.

You could either use pass-by-reference:

void test(int& a){

cin >> a;

}

or return the value

int test()

{

int a;

cin >> a;

return a;

}

int main()

{

int number = test();

cout << number;

}

cja · Answer

test's argument a is passed by value, so whatever you do to this argument inside the function does not change the actual parameter.

Try this: 
    void test(int &a) {
        cin >> a;
    }

Another option is :
    int test( ) {
        int a;
        cin >> a;
        return a;
    }

This is very simplistic, of course, not necessarily the best design or implementation.

EDIT: whoa ... while I was typing in my answer, Cubbi was entering his ... and they're almost identical, reassuring me that my answer is good :-)

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