[已解决]请问42行这里为什么会出现段错误

她的睫毛 · 发表于 2022-4-30 16:10:29

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#include <stdio.h>
#include <malloc.h>
#define initsize 10

struct list{
        int *data;
        int maxsize;
        int length;
};

//初始化顺序表
void Init_List(struct list *SeqList)
{
        SeqList->data = (int *)malloc(sizeof(int)*initsize);
        if(SeqList->data)
        {
                SeqList->length = 0;
                SeqList->maxsize = initsize;
                int i;
                for(i = 0; i < SeqList->maxsize; i++)
                        SeqList->data[i] = 0;
        }
}


//将顺序表填满
void Insert_Data(struct list *SeqList)
{
        int i;
        for(i = 0; i < SeqList->maxsize; i++)
                SeqList->data[i] = 1;
        SeqList->length = SeqList->maxsize;
}

//给顺序表扩容
struct list *Increase_space(struct list *SeqList, int len)
{
        int i;
        //重新开辟堆空间
        struct list *new_SeqList = NULL;
        printf("%d\n", __LINE__);
        new_SeqList->data = (int *)malloc(sizeof(int)*(SeqList->maxsize + len));
        new_SeqList->maxsize = SeqList->maxsize + len;
        new_SeqList->length = SeqList->maxsize;        
        for(i = 0; i < new_SeqList->length; i++)
                new_SeqList->data[i] = SeqList->data[i];
        //释放掉原堆空间
        free(SeqList->data);
}

//打印顺序表中的数据
void print_SeqList(struct list *SeqList)
{
        int i;
        for(i = 0; i < SeqList->length; i++)
                printf("%d\n", SeqList->data[i]);
}

int main()
{
        struct list SeqList;
        Init_List(&SeqList);
        Insert_Data(&SeqList);
        struct list *new_SeqList = Increase_space(&SeqList, 5);
        print_SeqList(new_SeqList);
        return 0;
}

最佳答案

月排行榜 / 总排行榜

人造人

2022-5-1 15:05:08

jackz007 发表于 2022-5-1 14:59
贴出错误信息看看

$ cat main.c
#include <stdio.h>
#include <malloc.h>
#define initsize 10

struct list{
        int *data;
        int maxsize;
        int length;
};

//初始化顺序表
void Init_List(struct list *SeqList)
{
        SeqList->data = (int *)malloc(sizeof(int)*initsize);
        if(SeqList->data)
        {
                SeqList->length = 0;
                SeqList->maxsize = initsize;
                int i;
                for(i = 0; i < SeqList->maxsize; i++)
                        SeqList->data[i] = 0;
        }
}


//将顺序表填满
void Insert_Data(struct list *SeqList)
{
        int i;
        for(i = 0; i < SeqList->maxsize; i++)
                SeqList->data[i] = 1;
        SeqList->length = SeqList->maxsize;
}

//给顺序表扩容
struct list *Increase_space(struct list *SeqList, int len)
{
        int i;
        //重新开辟堆空间
        struct list *new_SeqList = NULL;
        printf("%d\n", __LINE__);
        new_SeqList->data = (int *)malloc(sizeof(int)*(SeqList->maxsize + len));
        new_SeqList->maxsize = SeqList->maxsize + len;
        new_SeqList->length = SeqList->maxsize;        
        for(i = 0; i < new_SeqList->length; i++)
                new_SeqList->data[i] = SeqList->data[i];
        //释放掉原堆空间
        free(SeqList->data);
}

//打印顺序表中的数据
void print_SeqList(struct list *SeqList)
{
        int i;
        for(i = 0; i < SeqList->length; i++)
                printf("%d\n", SeqList->data[i]);
}

int main()
{
        struct list SeqList;
        Init_List(&SeqList);
        Insert_Data(&SeqList);
        struct list *new_SeqList = Increase_space(&SeqList, 5);
        print_SeqList(new_SeqList);
        return 0;
}
$ gcc-debug -o main main.c
main.c: In function ‘Increase_space’:
main.c:49:1: warning: control reaches end of non-void function [-Wreturn-type]
   49 | }
      | ^
$ ./main 
41
main.c:42:27: runtime error: member access within null pointer of type 'struct list'
AddressSanitizer:DEADLYSIGNAL
=================================================================
==31965==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x561b6d9cf9a1 bp 0x7ffc485f7b20 sp 0x7ffc485f7ae0 T0)
==31965==The signal is caused by a WRITE memory access.
==31965==Hint: address points to the zero page.
    #0 0x561b6d9cf9a1 in Increase_space /tmp/main.c:42
    #1 0x561b6d9d0134 in main /tmp/main.c:64
    #2 0x7f334644c30f in __libc_start_call_main (/usr/lib/libc.so.6+0x2d30f)
    #3 0x7f334644c3c0 in __libc_start_main@GLIBC_2.2.5 (/usr/lib/libc.so.6+0x2d3c0)
    #4 0x561b6d9cf154 in _start (/tmp/main+0x3154)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /tmp/main.c:42 in Increase_space
==31965==ABORTING
$

跳转到最佳答案楼层

jackz007 · 发表于 2022-4-30 20:21:09

42 行有段错误？在我这里是正常编译、运行，编译器使用的是 VC17.1.5（VC 2022）及 gcc 11.2.0 Windows 版，除了在编译时有警告信息外，运行时一切正常。

她的睫毛 · 发表于 2022-5-1 14:45:53

jackz007 发表于 2022-4-30 20:21
42 行有段错误？在我这里是正常编译、运行，编译器使用的是 VC17.1.5（VC 2022）及 gcc 11.2.0 Window ...

我是在 Linux 环境下，用 gcc 编译的，确实无法编译。。。

jackz007 · 发表于 2022-5-1 14:59:47

她的睫毛发表于 2022-5-1 14:45
我是在 Linux 环境下，用 gcc 编译的，确实无法编译。。。

贴出错误信息看看

人造人 · 发表于 2022-5-1 15:05:08

jackz007 发表于 2022-5-1 14:59
贴出错误信息看看

$ cat main.c
#include <stdio.h>
#include <malloc.h>
#define initsize 10

struct list{
        int *data;
        int maxsize;
        int length;
};

//初始化顺序表
void Init_List(struct list *SeqList)
{
        SeqList->data = (int *)malloc(sizeof(int)*initsize);
        if(SeqList->data)
        {
                SeqList->length = 0;
                SeqList->maxsize = initsize;
                int i;
                for(i = 0; i < SeqList->maxsize; i++)
                        SeqList->data[i] = 0;
        }
}


//将顺序表填满
void Insert_Data(struct list *SeqList)
{
        int i;
        for(i = 0; i < SeqList->maxsize; i++)
                SeqList->data[i] = 1;
        SeqList->length = SeqList->maxsize;
}

//给顺序表扩容
struct list *Increase_space(struct list *SeqList, int len)
{
        int i;
        //重新开辟堆空间
        struct list *new_SeqList = NULL;
        printf("%d\n", __LINE__);
        new_SeqList->data = (int *)malloc(sizeof(int)*(SeqList->maxsize + len));
        new_SeqList->maxsize = SeqList->maxsize + len;
        new_SeqList->length = SeqList->maxsize;        
        for(i = 0; i < new_SeqList->length; i++)
                new_SeqList->data[i] = SeqList->data[i];
        //释放掉原堆空间
        free(SeqList->data);
}

//打印顺序表中的数据
void print_SeqList(struct list *SeqList)
{
        int i;
        for(i = 0; i < SeqList->length; i++)
                printf("%d\n", SeqList->data[i]);
}

int main()
{
        struct list SeqList;
        Init_List(&SeqList);
        Insert_Data(&SeqList);
        struct list *new_SeqList = Increase_space(&SeqList, 5);
        print_SeqList(new_SeqList);
        return 0;
}
$ gcc-debug -o main main.c
main.c: In function ‘Increase_space’:
main.c:49:1: warning: control reaches end of non-void function [-Wreturn-type]
   49 | }
      | ^
$ ./main 
41
main.c:42:27: runtime error: member access within null pointer of type 'struct list'
AddressSanitizer:DEADLYSIGNAL
=================================================================
==31965==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x561b6d9cf9a1 bp 0x7ffc485f7b20 sp 0x7ffc485f7ae0 T0)
==31965==The signal is caused by a WRITE memory access.
==31965==Hint: address points to the zero page.
    #0 0x561b6d9cf9a1 in Increase_space /tmp/main.c:42
    #1 0x561b6d9d0134 in main /tmp/main.c:64
    #2 0x7f334644c30f in __libc_start_call_main (/usr/lib/libc.so.6+0x2d30f)
    #3 0x7f334644c3c0 in __libc_start_main@GLIBC_2.2.5 (/usr/lib/libc.so.6+0x2d3c0)
    #4 0x561b6d9cf154 in _start (/tmp/main+0x3154)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /tmp/main.c:42 in Increase_space
==31965==ABORTING
$

她的睫毛 · 发表于 2022-5-2 02:20:12

jackz007 发表于 2022-5-1 14:59
贴出错误信息看看

41 行这里我设置了一个 NULL 指针，所以后面就报错了。

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