引用的基本概念

cpp 评论

引用的基本概念

给变量起别名

规则

1 引用没有定义,是一种关系型声明。声明它和原有某一变量(实体)的关
系。故 而类型与原类型保持一致,且不分配内存。与被引用的变量有相同的地
址。

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#include<iostream>

using namespace std;

int main(int argc, char* argv[])
{
	int a = 100;

	int & re = a;

	cout << "&a = " << &a << endl;
	cout << "&re = " << &re << endl;

	return 0;
}

1619099566174

2 声明的时候必须初始化,一经声明,不可变更。

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#include<iostream>

using namespace std;

int main(int argc, char* argv[])
{
	int a = 100;
	//int &re; //Error
	int &re = a;
	cout << re << endl;

	return 0;
}

3 可对引用,再次引用。多次引用的结果,是某一变量具有多个别名。

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#include<iostream>

using namespace std;

int main(int argc, char* argv[])
{
	int a = 100;
	//int &re; //Error
	int &re = a;
	int &re2 = re;
	cout << re << endl;
	cout << re2 << endl;
	cout << &a << endl;
	cout << &re << endl;
	cout << &re2 << endl;

	return 0;
}

4 &符号前有数据类型时,是引用。其它皆为取地址。

引用做函数参数或函数返回值

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#include<iostream>

using namespace std;

typedef struct student
{
	char name[50];
	float score;
	int sex;
}Student;
//交换两个变量的值
int my_swap(int &a, int &b)
{
	int tem = a;
	a = b;
	b = tem;
	return 0;
}
//打印结构体变量
Student & my_print(Student &a)
{
	cout << a.name << endl;
	cout << a.score << endl;
	cout << a.sex << endl;

	return a;
}



int main(int argc, char* argv[])
{
	Student XiaoMing = { "XiaoMing",100.0f,1 };

	int a = 100, b = 90;

	cout << "a = " << a << endl;
	cout << "b = " << b << endl;
	cout << "--------------------------------" << endl;
	my_swap(a, b);
	my_print(XiaoMing);
	cout << "--------------------------------" << endl;
	cout << "a = " << a << endl;
	cout << "b = " << b << endl;

	return 0;
}

YanChen

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