用初始化值定义的
以下代码给出分段错误：
#include <stdio.h>
int main()
{
char* str = "hello world";
str[0] = 'H'; // it is throwing segmentation fault.
printf("%s",str);
return 0;
}
char指针进入只读段。要在以后的代码中修改它们，您需要使用malloc()或calloc()函数将其存储在堆内存中，或者将它们定义为数组。必须读取
无法更改：
char *ptr1 = "Hello, World!";
可以更改：
char ptr2[] = "Hello, World!";
堆内存示例：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void){
char *str = calloc(14, sizeof(char));
strcpy(str, "Hello, World!");
printf("Before: %sn", str);
str[0] = 'Q';
printf("After: %sn", str);
free(str); // heap-allocated memory must be freed
return EXIT_SUCCESS;
}
数组(堆栈分配内存(示例：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void){
char str[14] = {}; // decayed to pointer, but `sizeof()` operator treats this as an array in C
strcpy(str, "Hello, World!");
printf("Before: %sn", str);
str[0] = 'Q';
printf("After: %sn", str);
return EXIT_SUCCESS;
}