Question

在用户输入他们的名字和姓后，我需要程序做多件事情都很好，除了我需要编程以相反的顺序打印他们的名字（John Doe = Doe John）。我认为我有适当的功能，因为我收到了你们的帮助，但我仍然遇到了分段错误。这有什么问题。

这是该计划的最后一项功能

#include <stdio.h>
#include <string.h>

int main ()
{
    printf("Enter your first and last name\n");

    char name [25]={'\0'};
    char * space;

    fgets(name,sizeof(name),stdin);

    printf("You Entered: %s     \n", name);

    printf("There are %u characters in your name including the space. \n", strlen(name));

    char end;
    int i;
    end = strlen(name) -1;
    printf("Your name backwards is");
    for (i = end; i >= 0; --i)
    {
        printf("%c", name [i]);
    }

    printf("\nLooking for the space in your name \n", name);
    space=strchr(name, ' ');
    while (space!=NULL)
    {
        printf("The space was found at character %d\n", space-name+1);
        space=strchr(space+1, ' ');
    }
    //Why am I getting a segmentation fault (cord dumped) error here?
    *space = '\0';
    printf(" %s %s ", space+1, name);

}

Answer 1

当while循环中断space为NULL时，您正在写入NULL地址。

while (space!=NULL) <-- "loop breaks when space is NULL"
{
    printf("The space was found at character %d\n", space-name+1);
    space=strchr(space+1, ' ');
}
//Why am I getting a segmentation fault (cord dumped) error here? 
*space = '\0';  <--- "space is NULL"

修改

要以相反的顺序打印输入的单词，请尝试以下代码（阅读注释以了解）：

// suppose name is "Grijesh Chauhan" char *last = NULL, *firstspcae = NULL; firstspcae = space = strchr(name, ' '); *firstspcae = '\0'; // At first space insert nul char '\0' while (space != NULL) { printf("The space was found at character %d\n", space-name+1); last = space + 1; //next to space space=strchr(space + 1, ' '); } printf("\n%s %s ", last, name); // "Chauhan Grijesh" *firstspcae = ' '; // recover your original string back printf("\n%s %s ", last, name); // "Grijesh Chauhan"

Answer 2

更常见的方法是找出您获得segfault的行，使用gcc标记（例如-g）使用gcc -g file.c编译您的程序，然后运行{{1 （例如gdb'）然后键入gdb a.out然后run它应该给你segfault的行（或任何类型的错误）及其背后的原因

为什么我会出现分段故障（线路丢弃）？

2 个答案: