c - 如何从此列表中删除节点然后打印它？

Question

主要思想:制​​作一个食物+卡路里的列表，打印它，询问要删除的条目，然后打印包含已删除条目的列表。似乎无法使其工作。

我最初只想打印初始列表，但后来决定还要求用户删除特定条目并再次打印列表。这是我未能使其发挥作用的地方。

编译器给出的错误是:

1.[Error] 'struct info' has no member named 'current'(lines 91 and 99 in function deleteNode)
2.[Error] dereferencing pointer to incomplete type (in function printList)

这是我到目前为止的代码:

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

struct info {
int calories;
char name[100];
struct info *next;
};

void add_info(struct info *s);
struct info *create(void);
void printList();
void deleteNode ();

int main()
{
struct info *first;
struct info *current;
struct info *new;      
int x, i, y;

printf("\t\tHow many entries do you want? ");
scanf("%d",&x);

first = create();
current = first;

for(i=0;i<x;i++)
{
    if(i==0)
    {

        first = create();
        current = first;
    }
    else
    {
        new = create();
        current->next = new;
        current = new;
    }
    add_info(current);
}
current->next = NULL;

current = first;       
while(current)
{
    printf("\n\nCalories per food:  %d\t Name of the food: %s\n",current->calories,current->name);
    current = current->next;
}
printf("Which entry would you like to remove? ");
scanf("%d", &y);
deleteNode(y);
printf("The list after deletion is: ");
printfList();

return(0);
}


void add_info(struct info *s)
{
printf("Insert number of calories: ");
scanf("%d",&s->calories);
printf("\n Insert name of the food: ");
scanf("%s",&s->name);
s->next = NULL;
}


struct info *create(void)
{
struct info *initial;

initial = (struct info *)malloc(sizeof(struct info));
if( initial == NULL)
{
    printf("Memory error");
    exit(1);
}
return(initial);
}

void deleteNode(struct info **s, int y)
{

struct info* temp = *s, *prev;


if (temp != NULL && temp->current == y)
{
    *s = temp->next;  
    free(temp);              
    return;
}


while (temp != NULL && temp->current != y)
{
    prev = temp;
    temp = temp->next;
}


if (temp == NULL) return;


prev->next = temp->next;

free(temp);
}

void printList(struct list *info)
{
while (info != NULL)
{
    printf(" %d %s ", info->calories, info->name);
    info = info->next;
}
}

Answer 1

1.[Error] 'struct info' has no member named 'current'(lines 91 and 99 in function deleteNode)

看看这个声明:

struct info {
    int calories;
    char name[100];
    struct info *next;
};

然后你有一个像这样的变量声明:

struct info* temp = *s

你尝试像这样使用它:

temp->current

但是info结构中没有名称current。还有其他三个名字。您需要决定其中哪一个最适合您想要做的事情。

2.[Error] dereferencing pointer to incomplete type (in function printList)

看这行代码:

void printList(struct list *info)

您没有声明struct list，并且您正在声明一个名为info的变量，它与struct info不同 您已经声明了。相反，你需要这样的东西:

void printList(struct info* list)

这声明了一个名为list的参数，它是一个指向struct info的指针。现在，在 printList() 函数中只要有 info，就需要说 list。