Question

我尝试编写基本的链表代码。我有两个函数将数据添加到列表的开头和列表的结尾。每次在开头添加数据的功能都可以正常工作。

我总是在insert_end函数中遇到分段错误。在对temp1执行malloc之后尝试访问insert_first指针时，我收到错误。但这与我在struct node *temp1,*trav; temp1 = (struct node *)malloc(sizeof(struct node)); trav = (struct node *)malloc(sizeof(struct node)); if (temp1 != NULL) { //******************Segmentation fault at this line********** temp1->data = input; } #include<stdio.h> #include<stdlib.h> //*******Structure to hold linked list*********// struct node { int data; struct node *next; }*head,*temp; //***********Function to Display everything**********// void display(struct node *head) { struct node *trav; trav= (struct node *)malloc(sizeof(struct node)); printf("Entering into Display\n"); if (head == NULL) { printf("Oh My God, the list is empty\n"); } else { trav = head; while (trav != NULL) { printf("Value stored in [%p] is [%d]\n",trav,trav->data); trav = trav->next; } } } //***********Function to Insert at beginning*********// struct node *insert_first(struct node *head,int input) { temp = (struct node *)malloc(sizeof(struct node)); temp->data = input; printf("\nEntering insert first"); if (head == NULL) { head = temp; head->next = NULL; } else { temp->next = head; head = temp; } return head; } //**************Function to Insert at End******************// struct node *insert_last(struct node *head,int input) { struct node *temp1,*trav; temp1 = (struct node *)malloc(sizeof(struct node)); trav = (struct node *)malloc(sizeof(struct node)); if (temp1 != NULL) { temp1->data = input; } else { printf("empty"); } printf("\nEntering insert last"); if (head == NULL) { head = temp1; head->next = NULL; } else { trav = head; while (trav != NULL) { trav = trav->next; } trav->next = temp1; } return head; } //*************Main Fucntion***********// int main() { int choice,value; head = NULL; while(1) { printf("\n******Please Enter your choice****\n1. To insert at beginning\n2. To insert at End\n3. To Insert middle\n4. To delete\n5. To display\n0. To Exit\n"); scanf("%d",&choice); switch(choice){ case 1: printf("Please Enter the value to be added\n"); scanf("%d",&value); head = insert_first(head,value); break; case 2: printf("Please Enter the value to be added\n"); scanf("%d",&value); head = insert_last(head,value); break; case 5: display(head); break; case 0: return 0; default: printf("Thats a wrong choice\n"); break; } } }函数中所做的事情完全相同，但每次都有效。我试着谷歌搜索并在论坛中尝试，没有答案。请帮忙。

此链接是我确切的问题..但我完全不了解解决方案

Segmentation fault in C with malloc

我在这个块上特别容易出错

{{1}}

Answer 1

这是一个有问题的障碍。

else {
    trav = head;
    while (trav != NULL) {
        trav = trav->next;
    }
    trav->next = temp1;

当您离开while循环时，trav为NULL。这就行了

    trav->next = temp1;

因违反分段而失败。

将该块更改为：

else {
    trav = head;
    while (trav->next != NULL) {
        trav = trav->next;
    }
    trav->next = temp1;

在为结构指针执行malloc时出现分段错误

1 个答案: