c - 修改 char * const pstr = "abcd"时出现段错误；

Question

char * const pstr = "abcd";pstr 是一个指向 char 的 const 指针...我认为我不能修改pstr，但我可以修改*pstr，所以我编写了下一个代码

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
    //  The pointer itself is a constant，
    //  Point to cannot be modified，
    //  But point to a string can be modified
    char * const pstr = "abcd";  //  Pointer to a constant

    // I find that pstr(the address of "abcd") is in ReadOnly data
    // &pstr(the address of pstr) is in stack segment
    printf("%p  %p\n", pstr, &pstr);

    *(pstr + 2) = 'e';  //  segmentation fault (core dumped)
    printf("%c\n", *(pstr + 2));

    return EXIT_SUCCESS;
}

但是结果却并不如我所想。我在第 14 行遇到段错误(核心转储)...所以我编写了下一个代码

#include <stdio.h>
#include <stdlib.h>


int main(void)
{
    //  The pointer itself is a constant，
    //  Point to cannot be modified，
    //  But point to a string can be modified
    char * const pstr = "abcd";  //  Pointer to a constant

   // I find that pstr(the address of "abcd") is in ReadOnly data
   // &pstr(the address of pstr) is in Stack segment
   printf("%p  %p\n", pstr, &pstr);

   *(pstr + 2) = 'e';  //  segmentation fault (core dumped)
   printf("%c\n", *(pstr + 2));

   return EXIT_SUCCESS;

}

但我不知道为什么？？？

Answer 1

char * const pstr = "abcd"; 

pstr 是指向 char 的常量指针，您无法正确修改 pstr ，但 "abcd" > 是一个字符串迭代。并且您无法修改字符串文字。

您尝试修改它，因此出现段错误。