Question

正如我所说，链接列表存在问题。

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

#define MAX 30

typedef struct elem{
    char name[MAX];
    int statistic;
    int price;
    struct elem *next;
    struct elem *prev;
}   shop;

我在链接列表中搜索单词的功能，然后我想在main中将所有变量作为tmpname，tmpstatistic和tmpprice，并将它们用于其他事情。

void search(shop *first, char word[MAX], char tmpname[MAX], int tmpstatistic, int tmpprice)
{
    while (first!=NULL && strcmp(first->name, word) != 0)
    {
        first = first->next;
    }

    if (first != NULL && strcmp(first->name, word)==0)
    {
        printf("%s found! \n", word);
        printf("%s \n", first->name);
        printf("%d \n", first->statistic);
        printf("%d \n", first->price);
        tmpname=first->name;
        tmpstatistic=first->statistic;
        tmpprice=first->price;
    }
}

当我在功能中打印它时它可以工作但是当我想在主要打印tmp时它们是错误的。如果你能帮助我做些什么来获得主要的好的tmp变量。我不擅长编码：/

Answer 1

好吧，你的函数采用tmpname，tmpstatistic和tmpprice参数按值。这意味着你在main中传递的主要是复制，并且在函数中为副本分配了有意义的值，但是你在main中传递的变量保持不变。通过指针传递这些参数！

void search(shop *first, char word[MAX], char** tmpname, int* tmpstatistic, int* tmpprice)

然后使用，例如，

*tmpstatistic=first->statistic;

Answer 2

您必须将指针传递给函数search以获取值。因此，您可以设置指针引用的结果。

void search(shop *first, char word[MAX], char **tmpname, int* tmpstatistic, int* tmpprice)
                                           // ^             ^                  ^
{
    while (first!=NULL && strcmp(first->name, word) != 0)
    {
        first = first->next;
    }

    if (first != NULL && strcmp(first->name, word)==0)
    {
        printf("%s found! \n", word);
        printf("%s \n", first->name);
        printf("%d \n", first->statistic);
        printf("%d \n", first->price);
        *tmpname=first->name;           // assigne pointer to first->name where tmpname refers to
        *tmpstatistic=first->statistic; // assigne first->statistic where tmpstatistic refers to
        *tmpprice=first->price;         // assigne first->pricewhere tmppricerefers to
    }
}

如果您需要“名称”的副本，请使用strcpy( *tmpname, first->name );

这样称呼：

search(first,word[MAX],&tmpname, &tmpstatistic, &tmpprice);

另一个解决方案是返回指向列表中的found元素的指针，如果你找不到它，则返回NULL：

shop* search(shop *first, char word[MAX])
{
    while (first!=NULL && strcmp(first->name, word) != 0)
    {
        first = first->next;
    }

    return first; // If you didn't find word in list, first is NULL, else first is the found elment
}

在链接列表中搜索字符串并获取所有变量

2 个答案: