Call by reference:

Arguments to a function can be passed in two way; one by call by value and other by call

by reference.  Call by value is passed either through a constant or variable.  The call by reference is passed through address operator (&).  In C the function definition argument must be declared as pointer variable to pass by reference, where as in C++ the call by reference can be used without declaring the function arguments as pointer variables.  But in C++ both pointer argument method and without pointer argument can be adopted.

void f_ref(int &a, int &b); // void f_ref(int, int) is wrong for reference variable;

void main( )

{int a, b;

f_ref(a, b); // The value a is 10 and b is 20.

}

void f_ref(int &x, int &y)

{x =10;

y=20;

}