分配指针值

Question

我是 C 语言的初学者，不理解指针、字符串等可能很简单的概念

源码如下

#include<stdio.h>
int main(void){
char *p="Internship ";
printf("%s\n", p);
printf("%c\n", *p++);
printf("%c\n", *p+2);
printf("%c\n", *(p+6));
printf("%c\n", *++p);
printf("%c\n", *p--);
printf("%c\n", *(p+5));
printf("%c\n", *p);
return 0;
}

输出为

请尽可能详细地解释代码和输出。你会帮助我很多。提前谢谢你。

Answer 1

这是指针算术和值算术的混淆组合，结合了前缀和后缀 increment/decrement。

#include<stdio.h>
int main(void){
char *p="Internship "; /* creates a pointer p that points to the memory area
                          that contains the String Internship */
printf("%s\n", p);     /* This prints the string that p points to */
printf("%c\n", *p++);  /* This prints the character that p points to (I)
                          and then increments the address contained in p */
printf("%c\n", *p+2);  /* This prints the character that p points to (n),
                          but adds 2 to the value 'n' + 2 = 'p' (in ASCII) */
printf("%c\n", *(p+6)); /* This prints the character 6 ahead of what p points
                          to (h) */
printf("%c\n", *++p);  /* This prints the character the successor of p's value
                          points to (t). p is incremented */
printf("%c\n", *p--);  /* This prints the character that p points to (t), and
                          then decrements the value of p */
printf("%c\n", *(p+5)); /* This prints the character 5 ahead of the character
                          p points to (s), but doesn't change p */
printf("%c\n", *p);    /* This again prints the character p points to (n) */
return 0;
}

我希望我在你的代码中的评论能帮助你理解发生了什么。

分配指针值

Assigning pointer values

c

string

pointers

dereference