char *str=“STRING"之间的区别和 char str[] = “字符串"?

本文介绍了char *str=“STRING"之间的区别和 char str[] = “字符串"?的处理方法，对大家解决问题具有一定的参考价值

问题描述

在编写一个从字符串中删除特定字符的简单函数时，我遇到了一个奇怪的问题:

While coding a simple function to remove a particular character from a string, I fell on this strange issue:

void str_remove_chars( char *str, char to_remove)
{
    if(str && to_remove)
    {
       char *ptr = str;
       char *cur = str;
       while(*ptr != '')
       {
           if(*ptr != to_remove)
           {
               if(ptr != cur)
               {
                   cur[0] = ptr[0];
               }
               cur++;
           }
           ptr++;
       }
       cur[0] = '';
    }
}
int main()
{
    setbuf(stdout, NULL);
    {
        char test[] = "string test"; // stack allocation?
        printf("Test: %s
", test);
        str_remove_chars(test, ' '); // works
        printf("After: %s
",test);
    }
    {
        char *test = "string test";  // non-writable?
        printf("Test: %s
", test);
        str_remove_chars(test, ' '); // crash!!
        printf("After: %s
",test);
    }

    return 0;
}

我不明白为什么第二次测试失败了?在我看来，第一个符号 char *ptr = "string"; 等同于这个:char ptr[] = "string";.

What I don't get is why the second test fails? To me it looks like the first notation char *ptr = "string"; is equivalent to this one: char ptr[] = "string";.

不是这样吗?

推荐答案

两个声明不一样

char ptr[] = "string"; 声明一个大小为 7 的 char 数组并用字符
s 对其进行初始化,t,r,i,n,g 和 .您被允许修改此数组的内容.


char ptr[] = "string"; declares a char array of size 7 and initializes it with the characters
 s ,t,r,i,n,g and . You are allowed to modify the contents of this array.
char *ptr = "string"; 将 ptr 声明为 char 指针，并使用 string literal " 的地址对其进行初始化string" 是只读的.修改字符串文字是一种未定义的行为.您所看到的(段错误)是未定义行为的一种表现.
char *ptr = "string"; declares ptr as a char pointer and initializes it with address of string literal "string" which is read-only. Modifying a string literal is an undefined behavior. What you saw(seg fault) is one manifestation of the undefined behavior.

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char *str=“STRING"之间的区别和 char str[] = “字符串"?

问题描述

推荐答案

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