(持续更新中!!~)15、原来可以这样理解C语言_理解指针(3/3)指针运算笔试题解析-优快云博客

3. 指针运算笔试题解析

3.1 题⽬1：

#include <stdio.h>

int main()
{
 int a[5] = { 1, 2, 3, 4, 5 };
 int *ptr = (int *)(&a + 1);
 printf( "%d,%d", *(a + 1), *(ptr - 1));
 return 0;
}

//程序的结果是什么？

3.2 题⽬2

//在X86环境下 

//假设结构体的⼤⼩是20个字节 

//程序输出的结果是啥？ 

struct Test

{
int Num;
 char *pcName;
 short sDate;
 char cha[2];
 short sBa[4];
}*p = (struct Test*)0x100000;

int main()
{
 printf("%p\n", p + 0x1);
 printf("%p\n", (unsigned long)p + 0x1);
 printf("%p\n", (unsigned int*)p + 0x1);
 return 0;
}

3.3 题⽬3

#include <stdio.h>

int main()
{
 int a[3][2] = { (0, 1), (2, 3), (4, 5) };
 int *p;
 p = a[0];
 printf( "%d", p[0]);
 return 0;
}

3.4 题⽬4

//假设环境是x86环境，程序输出的结果是啥？ 

#include <stdio.h>

int main()
{
 int a[5][5];
 int(*p)[4];
 p = a;
 printf( "%p,%d\n", &p[4][2] - &a[4][2], &p[4][2] - &a[4][2]);
 return 0;
}

3.5 题⽬5

#include <stdio.h>

int main()
{
 int aa[2][5] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
 int *ptr1 = (int *)(&aa + 1);
 int *ptr2 = (int *)(*(aa + 1));
 printf( "%d,%d", *(ptr1 - 1), *(ptr2 - 1));
 return 0;
}

3.6 题⽬6

#include <stdio.h>

int main()
{
 char *a[] = {"work","at","alibaba"};
 char**pa = a;
 pa++;
 printf("%s\n", *pa);
 return 0;
}

3.7 题⽬7

#include <stdio.h>

int main()
{
 char *c[] = {"ENTER","NEW","POINT","FIRST"};
 char**cp[] = {c+3,c+2,c+1,c};
 char***cpp = cp;
 printf("%s\n", **++cpp);
 printf("%s\n", *--*++cpp+3);
 printf("%s\n", *cpp[-2]+3);
 printf("%s\n", cpp[-1][-1]+1);
 return 0;
}