c++将引用作为函数的参数---6

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引用经常被用作函数参数，使得函数中的变量名成为调用程序中的变量别名。这种传递参数 的方法称为按引用传递。按引用传递允许被调用的函数能够访问调用函数中的变量。C++新增这项特性是对C语言的超越，C语言只能按值传递。按值传递导致被 调用函数使用调用程序的值得拷贝。当然，C语言也允许避开按值传递的限制，采用按指针传递的方式。

代码：

#include <stdio.h>
#include <iostream>

using namespace std;

void TestAddress1(int p, int& a, int b)
{
cout << "TestAddress1" << endl;
cout << "p address:" << &p << "; p value:" << p << endl;
cout << "a address:" << &a << "; a value:" << a << endl;
cout << "b address:" << &b << "; b value:" << b << endl;

int* c = &b;
c -= 2;
cout << "c address:" << c << "; c value:" << *c << endl;
}

void TestAddress2(int* a, int b)
{
cout << "TestAddress2" << endl;
cout << "a address:" << &a << "; a value:" << *a << endl;
cout << "b address:" << &b << "; b value:" << b << endl;
}

int main()
{
int* a = new int[5];
memset(a, 0, sizeof(int)* 5);
a[0] = 123;
int b = 2;
int c = 3;

cout << "out a address:" << &a << endl;
cout << "out b address:" << &b << endl;
cout << "out c address:" << &c << endl;

cout << "-----------------" << endl;

TestAddress1(b, b, c);

cout << "-----------------" << endl;

TestAddress2(a, b);
}