int  main() {

    //引用的类型必须相同，一经引用，不可以在被引用

    int a = ;

    int  &b = a;//b引用a之后，两个同时都会改变，此时b已经指向a了，如果在来一个c的话，不能在去指向c。b和a的类型必须相同

    b = ;//必须初始化，int就是初始化,实质上是*b=304,默认会加上*

    printf("a:%d,b:%d\n", a, b);

}

//给数组起别名

int  main() {

    int  arr[];

    for (int i=;i < ;i++) {

        arr[i] = i;

    }

    //用&引用，起别名

    int (&parr)[] = arr;//用parr引用arr，相当于是arr重新赋值给了parr

    for (int i = ;i < ;i++) {

        cout << parr[i] << endl;

    }

}

    //第二种方式起别名

    typedef int Arrpy[];

    Arrpy  &parr2 = arr;

    for (int i = ;i < ;i++) {

        cout << parr2[i] << " ";

    }

    cout << endl;

void  swap1(int a,int b) {

    int temp = a;

    a = b;

    b = temp;

}

void  s1(){

    int a = ;

    int  b = ;

    swap(a, b);//传递；两个值进去

    cout << "a:" << a << "   b:"<<b << endl;

}

//指针传递

void  swap2(int  *a,int  *b) {

    int temp = *a;

    *a = *b;

    *b = temp;

}

void  s2() {

    int  a = ;

    int  b = ;

    swap2(&a, &b);

    cout << "a:" << a << "b:" << b << endl;

}

//引用传递

void  swap3(int  &a,int  &b) {

    int  temp = a;

    a = b;

    b = temp;

}

void   s3() {

    int  a = ;

    int  b = ;

    swap3(a, b);

    cout << "a:" <<a << "b:" << b << endl;

}

int  main() {

    s3();

}

int  & test07(){

    static  int  a = ;

    return  a;

}

int  main() {

    int  &res = test07();//内部就是int  * const  res=&test07();内部就是一个指针常量

    cout << res <<endl;

}

struct Person2

{

    int  age;

    string  name;

};

//利用指针来开辟空间

void  test10(Person2*  &p) {//这边引用,p就是传过来的指针，就是引用

    p = (Person2*)malloc(sizeof(Person2));

    p->age = ;

}

int  main() {

    Person2  *p1=NULL;

    test10(p1);//相当于传了一个指针过去,&p1>>>>>>>

    cout << "age" << p1->age << endl;

}

void  malloc1(Person2 **p) {

    //用指针来接收，**p就是person2对象，*p就是person2指针，p就是person对象的指针的指针

    *p = (Person2*)malloc(sizeof(Person2));//强制转换

    (*p)->age = ;

    cout << "age:" << (*p)->age << endl;

}

void  test11() {

    Person2  *p1=NULL;

    malloc1(&p1);//

}

int  main() {

    test11();

}