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尝试:为什么malloc错误来了

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运行我的尝试程序时,我一直收到错误 .

a.out:malloc.c:2372:sysmalloc:断言`(old_top ==(((mbinptr)(((char *)&((av) - > bins [((1) - 1)* 2]) ) - builtin_offsetof(struct malloc_chunk,fd))))&& old_size == 0)|| ((unsigned long)(old_size)> =(unsigned long)((( builtin_offsetof(struct malloc_chunk,fd_nextsize))((2 *(sizeof(size_t))) - 1))~~((2 *(sizeof( size_t))) - 1)))&&((old_top) - > size&0x1)&&((unsigned long)old_end&pagemask)== 0)'失败 .

我的代码是:

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

typedef struct nodeData
{
    char ch;                /* This structure looks like a linked list */
    struct nodeData *next;
}node;

typedef struct tries
{
    node *start[26];
}tries;

tries *makeAllNull(tries *root)
{
    int i=0;
    for(i=0;i<=26;i++)
    {
        root->start[i] = NULL;
    }
   return root;
}

/* Insert the given string in to the tries */
tries *insert(tries *root,char *str,int len)
{
    int i=0;
    tries *temp;
    temp = (tries *)malloc(sizeof(tries));
    while(i<len)
    {
        int k = str[i] - 'a';
        temp->start[k] = (node *)malloc(sizeof(struct nodeData));
        temp->start[k]->ch = str[i];
        temp->start[k]->next = NULL;
        if(temp->start[k] == NULL)
        {
            root->start[k] = temp->start[k];
        }
        else{
                root->start[k]->next = temp->start[k];
            }
        i++;

    }
    return root;
}

int main()
{
    int i=0;
    tries *root;
    root = (tries *)malloc(sizeof(node *));
    makeAllNull(root);
    char str[30];
    while(i<5)
    {
        scanf("%s",str);
        root = insert(root,str,strlen(str));
    }
    return 0;
}

1 回答

  • 0

    malloc 之后, if(temp->start[k] == NULL) 几乎总是假的,导致在这一行引用dereference NULL 指针

    root->start[k]->next = temp->start[k];
    

    这会破坏记忆 .

    你的意思是 if(root->start[k] == NULL) 而不是 if(temp->start[k] == NULL)

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