Question

1. [C++ Language] Describe how the following call by reference works. Make a comment for each line.

void pxc(int& c, int& d)

{

    int k = c;

    c = d;

    d = k;

}

  

int main()

{

    int a = 15, b = 100;

    pxc(a, b);

}

Answer 1

Solution :

void pxc(int& c, int& d) // here c & d represent a & b if changed value in c , d change the actual value in a , b

{

    int k = c; // store the value of c in variable k

    c = d; // store the value of d in variable c

    d = k; // store the value of k in variable d

} // It's actually swapping values of the two variables

  

int main()

{

    int a = 15, b = 100; // initialize the value of a and b

    pxc(a, b); // here after calling the function a= 100 and b= 15

}

Note : reference variable represent the same variable, with other name. It's just like represent same variable with two names. If we change value in reference variable, it will change the actual value in original variable.