C语言16 取值运算符

“*”的几种用途

1. 乘法运算符

   int x = 1;
   int y = 2;
   int z = x * y;
   

2. 定义新的类型

   char x;
   char* x;
   

3. 取值运算符

   * + 指针类型的变量
   
   int* a =(int*)1;
   printf("%x \n",*(a +1));
   
   
   10:       int* a =(int*)1;
   00401028   mov         dword ptr [ebp-4],1
   11:       printf("%x \n",*(a +1));
   0040102F   mov         eax,dword ptr [ebp-4]
   00401032   mov         ecx,dword ptr [eax+4]
   00401035   push        ecx
   00401036   push        offset string "%x \n" (0042201c)
   0040103B   call        printf (00401070)
   00401040   add         esp,8
   
   当然这里运行的时候肯定出错 因为 1 是一个异常的不存在的地址
   

探测 * 指针类型 的类型

int*** a;
int***** b;
int******* c;
int* d;

//int x = *(a+1);
//int x = *(b++);
//int x = *(c-5);
//int x = *(d+6);

//总结
//    *加指针类型 的类型是 指针类型减去一个*

取值运算符举例

int x=1;                        int x =1;
int* p = &x;                    int* p = &x;
printf("%x %x \n",p,*(p));      int** p2 = &p;
*(p)=2;                         int*** p3 = &p2;
printf("%d \n",x);              int r = *(*(*(p3)));
                                printf("%d \n",r);