Question

我在C中创建了这个链表程序。它从a3data.txt中读取数据（此文本文件的内容在输出后粘贴，如下所示）。在文本文件中，INSERT和REMOVE是命令。我希望能够读取命令INSERT，并将下一个整数（下一行）插入列表中。 REMOVE命令应从列表中删除最后一个节点。正如您所看到的，我的删除功能无法正常工作，我不明白为什么。有人请帮我调试吗？

输出

linux@computer ~/Documents/Data Structures/a3/code $ gcc exercise4.3.3.c
linux@computer ~/Documents/Data Structures/a3/code $ ./a.out

INSERT            0 5
INSERT            0 5 3
INSERT            0 5 3 19
         REMOVE   0 5 3 19
INSERT            1
         REMOVE   0
         REMOVE   0
         REMOVE   0
INSERT            4
INSERT            4 25
INSERT            4 25 5
         REMOVE   0 25 5
INSERT            4
INSERT            4 874
         REMOVE   0 874
         REMOVE   0 874
INSERT            8
INSERT            8 75
INSERT            8 75 22
INSERT            8 75 22 6
         REMOVE   0 75 22 6
INSERT            9
INSERT            9 31
INSERT            9 31 1
         REMOVE   0 31 1
         REMOVE   0 31 1
INSERT            419
INSERT            419 55
         REMOVE   0 55
INSERT            5

文字文件

INSERT
5
INSERT
3
INSERT
19
REMOVE
INSERT
1
REMOVE
REMOVE
REMOVE
INSERT
4
INSERT
25
INSERT
5
REMOVE
INSERT
4
INSERT
874
REMOVE
REMOVE
INSERT
8
INSERT
75
INSERT
22
INSERT
6
REMOVE
INSERT
9
INSERT
31
INSERT
1
REMOVE
REMOVE
INSERT
419
INSERT
55
REMOVE
INSERT
5

CODE

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

struct node {
    int number;
    struct node *next;
};

/* prototypes */

void ins(struct node *llist, int number);
void rem(struct node *llist);
void sho(struct node *llist);

int main(void)
{
    int number;
    char command[6];
    struct node *llist;

    llist = (struct node *)malloc(sizeof(struct node));
    llist->number = 0;
    llist->next = NULL;

    FILE *file;
    file = fopen("a3data.txt", "r");

    if (file == NULL)
    {
        printf("\n----------------------------------------\n");
        printf("| Error.  Did not read file.  Exiting. |\n");
        printf("----------------------------------------\n\n");
        exit(1);
    }
    else
    {
        while ((fscanf(file, "%s", command)) != EOF)
        {
            if((strcmp(command, "INSERT"))==0)
                {
                    fscanf(file, "%d", &number);
                    printf("\nINSERT            ", number);
                    ins(llist, number);
                    sho(llist);
                }
            else if((strcmp(command, "REMOVE"))==0)
                {
                    printf("\n         REMOVE   ");                
                    rem(llist);
                    sho(llist);
                }
        }
    }

    printf("\n");
    free(llist);
    return(0);
}

void ins(struct node *llist, int number) 
{
    while(llist->next != NULL)
    {
        llist = llist->next;
    }

    llist->next = (struct node *)malloc(sizeof(struct node));
    llist->next->number = number;
    llist->next->next = NULL;
}

void rem(struct node *llist)
{
    struct node *temp;
    temp = (struct node *)malloc(sizeof(struct node));

    /* remove the node */
    temp = llist->next;
    free(llist);
    llist = temp; 

}

void sho(struct node *llist)
{
    while(llist->next != NULL)
    {
        printf("%d ", llist->number);
        llist = llist->next;
    }

    printf("%d", llist->number);
}

尝试解决方案（我认为它适用于LIFO）

void rem(struct node *llist)
{
    while(llist->next->next != NULL)
    {
        llist = llist->next;
    }

    llist->next = NULL;
}

C中的链表实现（调试 - 输出不正确）

0 个答案: