Sams Teach Yourself C++ in 21 Days

function rather than where it belongs—on the function being called. Listing 9.7 rewrites

the swap()function, using references.

LISTING9.7 swap()Rewritten with References

1: //Listing 9.7 Demonstrates passing by reference

2: // using references!

3: #include <iostream>

4:

5: using namespace std;

6: void swap(int &x, int &y);

7:

8: int main()

9: {

10: int x = 5, y = 10;

11:

12: cout << “Main. Before swap, x: “ << x << “ y: “

13: << y << endl;

14:

15: swap(x,y);

16:

17: cout << “Main. After swap, x: “ << x << “ y: “

18: << y << endl;

19:

20: return 0;

21: }

22:

23: void swap (int &rx, int &ry)

24: {

25: int temp;

26:

27: cout << “Swap. Before swap, rx: “ << rx << “ ry: “

28: << ry << endl;

29:

30: temp = rx;

31: rx = ry;

32: ry = temp;

33:

34:

35: cout << “Swap. After swap, rx: “ << rx << “ ry: “

36: << ry << endl;

37:

38: }

Main. Before swap, x:5 y: 10

Swap. Before swap, rx:5 ry:10

Swap. After swap, rx:10 ry:5

Main. After swap, x:10, y:5

OUTPUT

266 Day 9