C单链表抛出错误

Question

我正在尝试用 C 实现单链表，但我不断收到此错误:

*“./output.o/”中的错误:双重释放或损坏(fasttop):0x09dd008 *

我对 C 很陌生，认为我的实现非常好，但我似乎无法弄清楚这个问题来自哪里。任何帮助将不胜感激。

这是列表

#include <stdio.h>
#include "list.h"
#include <string.h>
list llInit(){
    list llist;
    llist.head = (node *)malloc(sizeof(node));
    llist.tail = (node *)malloc(sizeof(node));
    llist.curr = (node *)malloc(sizeof(node));
    return llist;
}

int llSize(list *myList){
    int count = 0;
    node *next = (node *)malloc(sizeof(node));
    if((*myList).head!=NULL){
        next = (*myList).head;
        while((*next).next!=NULL){
            count++;
            next = (*next).next;
        }
    }
    free(next);
    return count;
}

int llAddToFront(list *myList, char *toStore){
    if(toStore!=NULL){
        node *new = (node *)malloc(sizeof(node));
        (*new).string = (char *)malloc(sizeof(char));
        (*new).next = (node *)malloc(sizeof(node));
        (*new).string = strdup(toStore);
        if((*myList).head!=NULL){
            (*new).next = (*myList).head;
            if((*myList).head==(*myList).curr){
                (*myList).curr = new;
            }
            (*myList).head = new;
        }else{
            (*myList).head = new;
            (*myList).curr = new;
            (*myList).tail = new;
        }
        return 1;
    }
    return 0;
}

int llDeleteFirst(list *myList){
    if(llSize(myList)){
        if((*myList).curr==(*myList).head){
            (*myList).curr = (*myList).head->next;
        }
        (*myList).head = (*myList).head->next;
        free((*myList).head);
        return 1;
    }
    return 0;
}

int llAddToBack(list *myList, char *toStore){
    if(toStore!=NULL){
        node *new = (node *)malloc(sizeof(node));
        (*new).string = strdup(toStore);
        (*new).next = NULL;
        if((*myList).tail!=NULL){
            (*(*myList).tail).next = new;
            (*myList).tail = new;
        }else{
            (*myList).tail = new;
            (*myList).head = new;
            (*myList).curr = new;
        }
        return 1;
    }
    return 0;
}

int llInsertAfterCurr(list *myList, char *string){
    if(string!=NULL){
        node *new = (node*)malloc(sizeof(node));
        (*new).string = (char *)malloc(sizeof(char));
        (*new).next = (node *)malloc(sizeof(node));
        (*new).string = string;
        if((*myList).curr==NULL){
            (*myList).head = new;
            (*myList).curr = new;
            (*myList).tail = new;
        }else{
            (*new).next = (*(*myList).curr).next;
            (*(*myList).curr).next = new;
        }
        return 1;
    }
    return 0;
}

int llDeleteAfterCurr(list *myList){
    if(llSize(myList)&&(*myList).tail!=(*myList).curr){
        node *temp = (node *)malloc(sizeof(node));
        temp = (*(*(*myList).curr).next).next;
        free((*(*myList).curr).next);
        (*(*myList).curr).next = temp;
        free(temp);
        return 1;
    }
    return 0;
}

void llClear(list *myList){
    while(llSize(myList)){
        llDeleteFirst(myList);
    }
    (*myList).head = NULL;
    (*myList).tail = NULL;
    (*myList).curr = NULL;
}

int llNext(list *myList){
    if(llSize(myList)&&(*myList).curr!=(*myList).tail){
        (*myList).curr = (*(*myList).curr).next;
        return 1;
    }
    return 0;
}

int llRewind(list *myList){
    if(llSize(myList)){
        (*myList).curr = (*myList).head;
        return 1;
    }
    return 0;
}

int llIterate(list *myList, fun f){
    if(llSize(myList)){
        llRewind(myList);
        while((*myList).curr!=(*myList).tail){
            f((*(*myList).curr).string);
            llNext(myList);
        }
        return 1;
    }
    return 0;
}

以及我正在使用的简单测试

#include <stdio.h>
#include "list.h"

int main(){
    list myList = llInit();
    llAddToFront(&myList,"To my friends ");
    llAddToBack(&myList,"Hello");
    llInsertAfterCurr(&myList, "I say ");
    /* iterate list front to back */
    node *aNode = myList.head;
    while(aNode!=NULL) {
        printf("%s",aNode->string);
        aNode = aNode->next;
    }
    printf("\nClearing List\n");
    llClear(&myList);
    return 0;
}

Answer 1

这不是一个答案，但对于评论来说太多了。我不知道您的 struct 声明，但是查找链接列表中的项目数的迭代非常简单，根本不需要强制转换。

int llSize(list *myList){
    int count = 0;
    while (myList) {
        count++;
        myList = myList->next;
    }
    return count;
}