C语言19 指针取值的两种方式

C语言19 指针取值的两种方式

一级指针和多级指针

int i =100;

int* p1 = &i;  
int** p2 = &p1;  
int*** p3 = &p2;  
int**** p4 = &p3;  
int***** p5 = &p4  
int****** p6 = &p5;  
int******* p7 = &p6;

int****** px1 = *(p7); 
int***** px2 = *(px1); 
int**** px3 = *(px2); 
int*** px4 = *(px3); 
int** px5 = *(px4); 
int* px6 = *(px5); 
int px7 = *(px6); 

int px7 = *(*(*(*(*(*(*(p7))))))); 

*()与[]的互换表示

int* p = (int*)1;
printf("%d %d \n",p[0],*p);  //p[0] = *(p+0) = *p  

int** p = (int**)1;
printf("%d %d \n",p[0][0],**p);  
printf("%d %d \n",p[1][2],*(*(p+1)+2));

int*** p = (int***)1;
printf("%d %d \n",p[1][2][3],*(*(*(p+1)+2)+3));  

同理：
*(*(*(*(*(*(*(p7))))))))  
= *(*(*(*(*(*(p7+0)+0)+0)+0)+0)+0) 
= p7[0][0][0][0][0][0][0] 

总结

*(p+i) = p[i]  
*(*(p+i)+k) = p[i][k]  
*(*(*(p+i)+k)+m) = p[i][k][m]  
*(*(*(*(*(p+i)+k)+m)+w)+t) = p[i][k][m][w][t]  
*() 与 []可以相互转换