一道c语言指针题
请问这道题输出结果是多少?为什么?
main()
{
int a[5] = {1,2,3,4,5};
int *ptr = (int*)(&a+1);
printf("%d %d" , *(a+1), *(ptr-1));
}
[解决办法]
#include <stdio.h> int main(void) { int a[5]={1,2,3,4,5}; //假设a的地址为0x80000000,sizeof(int)=4 //假设是little-endian,则0x80000000-0x80000013的数据为: // addr: 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 // data: 01 00 00 00 02 00 00 00 03 00 00 00 04 00 00 00 05 00 00 00 int *ptr1=(int *)(&a+1); //ptr1 = 0x80000000+20=0x80000014 int *ptr2=(int *)((int )a+1); //ptr2 = 0x80000000+1 = 0x80000001 //&ptr1[-1] = 0x80000014-4 = 0x80000010,so ptr1[-1] = *(int *)0x80000010 = 5 //*ptr2 = *(int *)0x80000001 = 0x02000000 printf("%x,%x",ptr1[-1],*ptr2); return 0; } 这个解释的好。