将引用作为函数参数

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   
#include 

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);
}

将引用作为函数参数_第1张图片

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