#include <iostream>
using namespace std;
int main( )
{
    int a ;
    int &b = a;    //b和a實(shí)際上是同一變量
    b = 100;       //b賦值為100,，也就是a賦值為100
    cout << a << endl;
    //a的地址和b的地址應(yīng)該是完全一樣
    cout << &a << endl;
    cout << &b << endl;
    /*-------▼下面代碼有錯(cuò)，注釋后才能運(yùn)行▼-----------
    int x[] = {12,15,20} ;
    int &y = x;    //錯(cuò)誤：數(shù)組,、指針不能被引用
    int x1;
    int &y1;    //錯(cuò)誤：引用時(shí)必須初始化
    y1 = x1;
    -------▲上面代碼有錯(cuò),，注釋后才能運(yùn)行▲-----------*/
    return 0;
}

#include <iostream>
using namespace std;
                                                //|右邊為指針作參數(shù)的代碼，僅作比較用,。
void swap(int &x, int &y);                      //|void swap(int *x, int *y);
                                                //|
int main ( )                                    //|
{                                               //|
    int i = 12;                                 //|
    int j = 25;                                 //|
    cout << "i=" << i << "   j=" << j << endl;  //|
                                                //|
    swap(i, j);                                 //|swap(&i, &j);
    cout << "i=" << i << "   j=" << j << endl;  //|
                                                //|
    return 0;                                   //|
}                                               //|
                                                //|
void swap(int &x, int &y)                       //|void swap(int *x, int *y)
{                                               //|{
    int t;                                      //|    int t;
                                                //|
    t = x;                                      //|    t = *x;
    x = y;                                      //|    *x = *y;
    y = t;                                      //|    *y = *x;
}                                               //|}

#include <iostream>
using namespace std;
class myclass {
    int who;
public:
    myclass(int n) {
        who = n;
        cout << "構(gòu)造函數(shù)調(diào)用" << who << endl;
    }
    ~myclass() {
        cout << "析構(gòu)函數(shù)調(diào)用" << who << endl;
    }
    int id() {
        return who;
    }
};
void f1(myclass o) {    //普通變量方式傳遞參數(shù)
    cout << "外部函數(shù)調(diào)用" << o.id() << endl;
}
void f2(myclass *o) {    //指針?lè)绞絺鬟f參數(shù)
    cout << "外部函數(shù)調(diào)用" << o->id() << endl;
}
void f3(myclass &o) {    //引用方式傳遞參數(shù)
    cout << "外部函數(shù)調(diào)用" << o.id() << endl;
}
int main ( )
{
    myclass x1(1);
    f1(x1);
    cout << "-------" << endl;
    myclass x2(2);
    f2(&x2);
    cout << "-------" << endl;
    myclass x3(3);
    f3(x3);
    cout << "-------" << endl;
    return 0;
}

#include <iostream>
using namespace std;
int &f();
int x;
int main ( )
{
    f() = 100;
    cout << x << endl;
    return 0;
}
int &f()
{
    return x;
}