我的代码适用于一种编译器，但不适用于其他编译器

Question

linkedList.c:

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

struct Node {
    int data;
    struct Node *next;
};

typedef struct Node *node;

node createNode(int val) {
    node newNode = (node)malloc(sizeof(struct Node));
    if (newNode == NULL) {
        printf("cannot allocate memory");
        exit(EXIT_FAILURE);
    }
    newNode->data = val;
    newNode->next = NULL;
    return newNode;
}

node insertFront(node head, int val) {
    node insert = createNode(val);
    if (head == NULL) {
        head = insert;
        return head;
    }
    insert->next = head;
    head = insert;
    return head;
}

node insertTail(node head, int val) {
    node insert = createNode(val);
    node temp = head;
    if (head == NULL) {
        head = insert;
        return head;
    }
    while (temp->next != NULL)
        temp = temp->next;
    temp->next = insert;
    insert->next = NULL;
    return head;
}

node listSearch(node head, int val) {
    node temp = head;
    while (temp != NULL) {
        if (temp->data == val) {
            printf("%d\n", 1);
            return temp;
        }
        temp = temp->next;
    }
    printf("%d\n", -1);
    return NULL;
}

node insertAfter(node head, int afterThisVal, int val) {
    node afterThis = listSearch(head, afterThisVal);
    if (afterThis == NULL)
        return head;
    if (afterThis->next == NULL) {
        head = insertTail(head, val);
        return head;
    }
    node insert = createNode(val);
    node temp = afterThis->next;
    afterThis->next = insert;
    insert->next = temp;
    return head;
}

node insertBefore(node head, int beforeThisVal, int val) {
    node beforeThis = listSearch(head, beforeThisVal);
    if (beforeThis == NULL)
        return head;
    if (beforeThis == head) {
        head = insertFront(head, val);
        return head;
    }
    
    node prev = head;
    while (prev->next != beforeThis)
        prev = prev->next;

    node insert = createNode(val);
    prev->next = insert;
    insert->next = beforeThis;
    return head;
}

node deleteFirst(node head) {
    if (head == NULL) {
        printf("%d\n", -1);
        return head;
    }
    node temp = head;
    head = head->next;
    printf("%d\n", temp->data);
    free(temp);
    return head;
}

node deleteLast(node head) {
    if (head == NULL) { 
        printf("%d\n", -1);
        return head;
    }
    node temp = head;
    node prev = NULL;
    while (temp->next != NULL) {
        prev = temp;
        temp = temp->next;
    }
    if (prev != NULL)
        prev->next = NULL;
    printf("%d\n", temp->data);
    free(temp);
    return head;
}

node deleteNode(node head, int val) {
    node found = listSearch(head, val);
    if(found==NULL){
        printf("%d\n",-1);
        return head;
    }
    else if(found==head){
        head = deleteFirst(head);
        return head;
    }
    else if(found->next==NULL){
        head = deleteLast(head);
        return head;
    }
    node prev = head;
    while(prev->next!=found) prev = prev->next;
    prev->next = found->next;
    printf("%d\n",found->data);
    free(found);
    return head;
}

void display(node head){
    if(head==NULL) return;
    node temp = head;
    while(temp->next!=NULL){
        printf("%d ",temp->data);
        temp = temp->next;
    }
    printf("%d\n",temp->data);
}

node reverseList(node head){
    node i = head;
    node j = NULL;
    node k = NULL;

    while(i!=NULL){
        k=j;
        j=i;
        i=i->next;
        j->next = k;
    }
    return j;
}

node reverseEven(node head){
    node oddHead = head;
    node odd = head;
    node evenHead = head->next;
    node even = head->next;
    node temp1 = NULL;
    node temp2 = NULL;
    while(odd->next!=NULL && even->next!=NULL){
        odd->next = even->next;
        odd = odd->next;
        even->next = odd->next;
        even = even->next;
    }
    if((odd!=NULL && odd->next!=NULL) || (even!=NULL && even->next!=NULL)){
        odd->next = NULL;
        even->next = NULL;
    }
    display(evenHead);
    display(oddHead);
    evenHead = reverseList(evenHead);
    even = evenHead;
    odd = oddHead;
    while(even!=NULL && odd!=NULL){
        temp1 = odd;
        odd = odd->next;
        temp1->next = even;
        temp2 = even;
        even = even->next;
        temp2->next = odd;
    }
    return head;
}

int main(){
    char op[2];
    node head = NULL;
    int inp1,inp2;
    scanf("%s",op);
    while(strcmp(op,"e")!=0){
        if(strcmp(op,"f")==0){
            scanf("%d",&inp1);
            head = insertFront(head,inp1);
            display(head);
        }
        else if(strcmp(op,"t")==0){
            scanf("%d",&inp1);
            head = insertTail(head,inp1);
            display(head);
        }
        else if(strcmp(op,"a")==0){
            scanf("%d",&inp1);
            scanf("%d",&inp2);
            head = insertAfter(head,inp2,inp1);
            display(head);
        }
        else if(strcmp(op,"b")==0){
            scanf("%d",&inp1);
            scanf("%d",&inp2);
            head = insertBefore(head,inp2,inp1);
            display(head);
        }
        else if(strcmp(op,"d")==0){
            scanf("%d",&inp1);
            head = deleteNode(head,inp1);
            display(head);
        }
        else if(strcmp(op,"i")==0){
            head = deleteFirst(head);
            display(head);
        }
        else if(strcmp(op,"l")==0){
            head = deleteLast(head);
            display(head);
        }
        else if(strcmp(op,"s")==0){
            scanf("%d",&inp1);
            listSearch(head,inp1);
        }
        else if(strcmp(op,"r")==0){
            head = reverseList(head);
        }
        else if(strcmp(op,"ds")==0){
            display(head);
        }
        else if(strcmp(op,"re")==0){
            head = reverseEven(head);
        }
        else{
            printf("INVALID\n");
        }
        scanf("%s",op);
    }
    return 1;
}

我的代码将链表的所有功能实现为菜单驱动程序。

输入.txt

f 7
t 10
a 11 7
b 12 11
d 10
i
l
s 12
s 6
t 15
f 14
f 20
ds
r
re
e

我看到的错误是分段错误。 在 input.txt 中的 f 20 之后的 ds(display function) 处，head 随机获取一个垃圾值，它显示 mingw_ovr _bulletin_va_lists 部分 我不确定我犯了什么错误。

请原谅我在代码中可能使用的不好的做法，因为我仍在学习 C。

Answer 1

函数

deleteLast

有一个bug：必须测试

head

是否已经是最后一个节点，并在释放

NULL

后返回

temp

。当您取消引用无效指针时，在此之后读取

head

时，您会出现未定义的行为。未定义的行为意味着任何事情都可能发生，包括不同运行或不同计算机上的不同行为。

这是修改后的版本：

node deleteLast(node head) {
    if (head == NULL) { 
        printf("%d\n", -1);
        return head;
    }
    node temp = head;
    node prev = NULL;
    while (temp->next != NULL) {
        prev = temp;
        temp = temp->next;
    }
    if (prev == NULL) {
        head = NULL;
    } else {
        prev->next = NULL;
    }
    printf("%d\n", temp->data);
    free(temp);
    return head;
}