C/C++函数参数,传值域传址!!!

/*
* File: main.cpp
* Author: Vicky
*
* Created on 2010年5月8日, 下午2:47
*/
#include <iostream>
using namespace std;
void swap(int x, int y) {
cout << "x and y swap before : " << x << "\t" << y << endl;
int i = x;
x = y;
y = i;
cout << "x and y swap after : " << x << "\t" << y << endl;
}
void swap2(int * x, int * y) {
cout << "x and y swap before : " << *x << "\t" << *y << endl;
int * i = x;
x = y;
y = i;
cout << "x and y swap after : " << *x << "\t" << *y << endl;
}
/**
* 注意,此处非&x与&y并非地址,而是对象的别名!!!
*/
void swap3(int &x, int &y) {
cout << "x and y swap before : " << x << "\t" << y << endl;
int i = x;
x = y;
y = i;
cout << "x and y swap after : " << x << "\t" << y << endl;
}
/**
* 按址传递,传递的参数是地址.
*/
void swap4(int * x, int * y) {
cout << "x and y swap before : " << *x << "\t" << *y << endl;
int i = *x;
*x = *y;
*y = i;
cout << "x and y swap after : " << *x << "\t" << *y << endl;
}
int main(int argc, char** argv) {
int x = 1;
int y = 9;
cout << "main function swap before : " << x << "\t" << y << endl;
swap(x, y);
cout << "main function swap after : " << x << "\t" << y << endl;
// 可将,主函数的x与y并没有交换,表示swap函数交换的仅仅是x与y的副本
cout << "---------" << endl;
int * px = new int(1);
int * py = new int(9);
cout << "main function swap before : " << *px << "\t" << *py << endl;
swap2(px, py);
cout << "main function swap after : " << *px << "\t" << *py << en