c - 使用fgets()和strtok()读取文本文件以分隔行中的字符串，从而产生不必要的行为

Question

我试图使用fgets（）和strtok（）读取以下格式的文本文件。

1082018 1200 79 Meeting with President
2012018 1200 79 Meet with John at cinema
2082018 1400 30 games with Alpha
3022018 1200 79 sports

我需要将第一个值与行的其余部分分开，例如：

key=21122019, val = 1200 79 Meeting with President

为此，我将 strchr()用于 val和 strtok()用于 key，但是，从文件读取时，键值保持不变。我不明白为什么会发生这种情况，因为我在while循环中为in_键分配空间，并且每次都以不同的索引放置在数组中。
我的代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 1000 // max number of lines to be read
#define VALLEN 100
#define MAXC 1024

#define ALLOCSIZE 1000 /*size of available space*/
static char allocbuf[ALLOCSIZE]; /* storage for alloc*/
static char *allocp = allocbuf; /* next free position*/

char *alloc(int n) { /* return a pointer to n characters*/
    if (allocbuf + ALLOCSIZE - allocp >= n) { /*it fits*/
        allocp += n;
        return allocp - n; /*old p*/
    } else /*not enough room*/
        return 0;
}

int main(int argc, char** argv) {
    FILE *inp_cal;
    inp_cal = fopen("calendar.txt", "r+");

    char buf[MAXC];
    char *line[1024];
    char *p_line;

    char *in_val_arr[100];
    char *in_key_arr[100];
    int count = 0;
    char delimiter[] = " ";

    if (inp_cal) {
        printf("Processing file...\n");
        while (fgets(buf, MAXC, inp_cal)) {
            p_line = malloc(strlen(buf) + 1); // malloced with size of buffer.
            char *in_val;
            char *in_key;

            strcpy(p_line, buf);    //used to create a copy of input buffer
            line[count] = p_line;

            /* separating the line based on the first space. The words after
             * the delimeter will be copied into in_val */
            char *copy = strchr(p_line, ' ');
            if (copy) {
                if ((in_val = alloc(strlen(line[count]) + 1)) == NULL) {
                    return -1;
                } else {
                    strcpy(in_val, copy + 1);
                    printf("arr: %s", in_val);
                    in_val_arr[count] = in_val;
                }
            } else
                printf("Could not find a space\n");

            /* We now need to get the first word from the input buffer*/
            if ((in_key = alloc(strlen(line[count]) + 1)) == NULL) {
                return -1;
            }
            else {
                in_key = strtok(buf, delimiter);
                printf("%s\n", in_key);
                in_key_arr[count] = in_key; // <-- Printed out well
                count++;
            }
        }
        for (int i = 0; i < count; ++i)
            printf("key=%s, val = %s", in_key_arr[i], in_val_arr[i]); //<-- in_key_arr[i] contains same values throughout, unlike above
        fclose(inp_cal);
    }
    return 0;
}

while循环输出（正确）：

Processing file...
arr: 1200 79 Meeting with President
1082018
arr: 1200 79 Meet with John at cinema
2012018
arr: 1400 30 games with Alpha
2082018
arr: 1200 79 sports
3022018

对于循环输出（不正确）：

key=21122019, val = 1200 79 Meeting with President
key=21122019, val = 1200 79 Meet with John
key=21122019, val = 1400 30 games with Alpha
key=21122019, val = 1200 79 sports

有什么建议可以改进，为什么会这样？谢谢

Answer 1

您一次又一次地将同一指针存储在in_key_arr中。
你大概需要这个：

in_key = strtok(buf, delimiter);
printf("%s\n", in_key);
char *newkey = malloc(strlen(in_key) + 1);  // <<<< allocate new memory
strcpy(newkey, in_key);
in_key_arr[count] = newkey;                 // <<<< store newkey
count++;

免责声明：
为简洁起见，不进行错误检查
完成后，需要释放malloced内存。