c - 结构不取值

Question

我的作业有问题。任务是从 txt 文件中读取一个字符串，并将其与指向结构的指针数组进行比较。如果该字符串已经出现，则将该结构的计数加 1，如果未找到，则将该字符串插入计数为 1 的数组中。
结构已定义:

struct wordfreq {
    int count;
    char *word;
}

代码如下:

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

struct wordfreq {
    int count;
    char *word;
};

typedef struct wordfreq wordfreq;

int mystrcmp(char *str1, char *str2);


int main(int argc, char *argv[])
{
    int i, j, flag, current, spot;
    char *temp, *temp2;
    FILE *infile, *outfile;
    wordfreq *wordsptr[1000];
    if (argc != 3)
    {
        printf("Invalid number of arguments, exiting\n");
        return 1;
    }
    else 
    {
        infile = fopen(argv[1], "r");
        outfile = fopen(argv[2], "w");
        if (infile == NULL)
        {
            printf("Error opening input file, exiting\n");
            return 2;
        }
        if (outfile == NULL)
        {
            printf("Error opening output file, exiting\n");
            return 3;
        }
    }
    current = 0;
    flag = 0;
    for (i = 0; i < 1000; i++)
        wordsptr[i] = NULL;
    temp = (char *)calloc(20,sizeof(char));
    while (fgets(temp, 20, infile) != NULL)
    {
        flag = 0;
        for (i = 0; i < 20; i++)
            if (temp[i] == '\n')
                temp[i] = '\0';
        printf("%s %d\n", temp, current);
        wordsptr[current] = (wordfreq *)malloc(sizeof(wordfreq));
        wordsptr[current]->word = (char *)malloc(20*sizeof(char));
        (*wordsptr[current]).word = temp;
        (*wordsptr[current]).count = 1;
        current++;
    }
    for (i = 0; i < current; i++)
        printf("%d %s\n", (*wordsptr[i]).count, (*wordsptr[i]).word);




    free(temp);
    for (i = 0; i < 1000; i++)
    {
        wordsptr[i] = NULL;
        free(wordsptr[i]);
    }
    if (infile != NULL)
        fclose(infile);
    if (outfile != NULL)
        fclose(outfile);
    return 0;
}


int mystrcmp(char *str1, char *str2)
{
    int i;
    for (i = 0; str1[i] != '\0' || str2[i] != '\0';i++)
        if (str1[i] != str2[i])
            return 1;
    return 0;
}

一些规定:
1) 必须将所有指针初始化为空
2) 必须使用指向结构的指针数组

运行:./assign6 words.txt freq.txt

文字.txt:

apple
orange
apple
orange
banana
banana

我收到的输出: 1根香蕉 1根香蕉 1根香蕉 1根香蕉 1根香蕉 1根香蕉

应该输出txt文件中字符串的个数和字符串本身到argv[2]指定的文件中。请帮忙!

Answer 1

你正在分配 temp 的地址，它在每次迭代中不断更新为新值，因此你在这里获得所有结构中最后一次迭代的字符串。这是由以下几行引起的:

wordsptr[current]->word = (char *)malloc(20*sizeof(char));
(*wordsptr[current]).word = temp;

(值得一提的是，这也是内存泄漏，因为您丢失了指向堆内存的指针。)

您应该改为使用 strcpy() 或类似的方法将字符从 temp 复制到 wordsptr[current]->word。