005_linuxC++之_指针的引入

（一）直接看代码

 #include <iostream>
 using namespace std;
 int add(int a){
     a = a + ;
     return a;
 }
 int add(int *a){
     *a = *a + ;
     return *a;
 }
 int add_ref(int &b){
     b = b + ;
     return b;
 }
 int main(int arg,char ** argv){
     int a = ;
     int &c = a;                /*使用符号&来进行引用，引用之后c++就相当于a地址中的数进行a++*/
     cout<<add(a)<<endl;        /*传入的是参数*/  /*a = 100*/
     cout<<"a = "<<a<<endl;                      /*a = 99*/

     cout<<add(&a)<<endl;    /*传入的地址*/    /*a = 100*/
     cout<<"a = "<<a<<endl;                      /*a = 100*/

     cout<<add_ref(a)<<endl;    /*引用*/          /*a = 101*/
     cout<<"a = "<<a<<endl;                      /*a = 101*/

     c++;                                      /*a = 102*/
     cout<<"a = "<<a<<endl;                      /*a = 102*/
     cout<<"c = "<<c<<endl;                      /*a = 102*/
     return ;
 }

运行结果