C++——引用

最新推荐文章于 2025-06-23 21:27:21 发布

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最新推荐文章于 2025-06-23 21:27:21 发布

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本文链接：https://blog.youkuaiyun.com/Airaybaiju/article/details/79442144

本文深入讲解C++中引用的概念及其应用，包括定义、初始化、作为函数参数的不同方式，并通过实例对比了按值传递、按引用传递和按指针传递的区别。

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1.定义及表示

引用是已定义变量的别名，用&声明引用。

int price = 1;
int & prices = price;

prices是指向int变量的引用，price与其引用变量prices的值和地址都相同。

#include<iostream>
using namespace std;
int main()
{
	int x_ming = 50;
	int & l_ming = x_ming;
	cout << "x_ming: " << x_ming << "   l_ming: " << l_ming << endl;
	cout << "x_ming adress: " << &x_ming << "   l_ming adress: " << &l_ming << endl;
	int z_sang = 100;
	l_ming = z_sang;
	cout << "z_sang: " << z_sang << "   x_ming: " << x_ming << "   l_ming: " << l_ming << endl;
	cout << "z_sang adress: "<< &z_sang << "   x_ming adress: " << &x_ming << "   l_ming adress: " << &l_ming << endl;
	system("pause");
	return 0;
}

x_ming: 50 l_ming: 50
x_ming adress: 0017FBB0 l_ming adress: 0017FBB0
z_sang: 100 x_ming: 100 l_ming: 100
z_sang adress: 0017FB98 x_ming adress: 0017FBB0 l_ming adress: 0017FBB0

请按任意键继续. . .

（编故事）有一个人小名叫小明（x_ming）大名叫李明（l_ming），考试考了50分，嫉妒张三（z_sang）考试考了100分，于是，他把成绩单上的50分改成和张三一样的100分，拿回家给家长看，家长惊讶，遂call老师，查到教务处系统是50分，遂被教训。

int x_ming;
int & l_ming;
l_ming = x_ming;
//error:声明引用变量时初始化

引用更接近const指针，一旦和某个变量关联起来，必是生死相随。

int & l_ming = x_ming;
int * const p = &x_ming;

2.引用用作函数参数

按引用传递，按值传递，按指针传递。

#include<iostream>
using namespace std;
void swap_by_value(int a, int b)
{
	int temp;
	temp = a;
	a = b;
	b = temp;
}
void swap_by_point(int * a, int * b)
{
	int temp;
	temp = *a;
	*a = *b;
	*b = temp;
}
void swap_by_reference(int & a, int & b)
{
	int temp;
	temp = a;
	a = b;
	b = temp;
}
int main()
{
	int x_ming = 50;
	int z_sang = 100;
	cout << "x_ming: " << x_ming << "   z_sang:" << z_sang << endl;
	swap_by_value(x_ming, z_sang);
	cout << "swap_by_value result:\n" << "x_ming: " << x_ming << "   z_sang: " << z_sang << endl;
	swap_by_point(&x_ming, &z_sang);
	cout << "swap_by_point result:\n" << "x_ming: " << x_ming << "   z_sang: " << z_sang << endl;
	swap_by_reference(x_ming, z_sang);
	cout << "swap_by_reference result:\n" << "x_ming: " << x_ming << "   z_sang: " << z_sang << endl;
	system("pause");
	return 0;	
}

x_ming: 50 z_sang:100
swap_by_value result:
x_ming: 50 z_sang: 100
swap_by_point result:
x_ming: 100 z_sang: 50
swap_by_reference result:
x_ming: 50 z_sang: 100

请按任意键继续. . .

按引用传递和按指针传递都成功的实现了交换功能。