c - 从文件转换时间并与当前时间进行比较

Question

我之前问过一些类似的问题，但看起来，我从文件中获取的时间并没有转换为您从 localtime() 和 time() 中获取的相同类型的时间。

正是我想要的是:

我有一个包含以下信息的 txt 文件

订单.txt

file1.txt;5;15:40

file2.txt;7;15:41

file1.txt;10;16:00

我的目标是获取 hour:min (15:40) 的时间，然后，如果它与 currentTime 相同，则显示 file1.txt内容。否则，如果 currentTime 低于 hour:min 时间 (15:40)，它会等到 15:40 并显示file1.txt 内容。如果 currentTime 更高，则忽略第一个并转到下一个。

例如，如果当前时间是15:39，它将等待1分钟然后显示file1 .txt 内容。如果当前时间是15:40，则直接显示file1.txt内容，无需等待。如果当前时间是15:41，它只是转到下一个(file2.txt)并再次检查。

使用的变量

FILE* orderFile;
FILE* contentFile;
FILE* defaultFile; (This will be used when this code works)
char fileName[50];
char textContent[5000];
int seconds;
int hour, min;
int diff_time;
char timeValue[50];
time_t current;

包括

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

为此，我尝试了以下代码:

orderFile = fopen("order.txt","r");
defaultFile = fopen("default.txt","r");

while(fscanf(orderFile," %49[^;];%d; %49[^\n]",fileName,&seconds,timeValue)
{

  sscanf(timeValue,"%d:%d",&hour,&min);

  contentFile = fopen(fileName,"r");
            
  if(contentFile != NULL)
  {
     fseek (contentFile, 0, SEEK_END);
     size = ftell(contentFile);
     rewind(contentFile);
                    
     if(size == 0)
     {
       printf("\nEmpty file. (Scanned file: %s)\n", fileName);
       fclose(contentFile);
     }
     else
     {
                    
         time_t now;
                        time(&now);

                        struct tm file_time_tm;
                        file_time_tm = *localtime(&now);
                        file_time_tm.tm_hour = hour;
                        file_time_tm.tm_min = min;
                        file_time_tm.tm_sec = 0;
                        file_time_tm.tm_isdst = -1;
                        time_t fileTime = mktime(&file_time_tm);

                        double diff_time = difftime(fileTime, now);
                        
                        if(diff_time == 0) 
                        {
                            while(fscanf(contentFile,"%[^\t]",textContent) == 1)
                            {
                                printf("%s\n", textContent);
                            }
                            sleep(seconds);
                        }
                        else
                        {
                            if(diff_time > 0)
                            {
                                while(fscanf(defaultFile,"%[^\t]",defaultContent) == 1)
                                {
                                    printf("%s\n", defaultContent);
                                }
                                sleep(diff_time);
                                
                                while(fscanf(contentFile,"%[^\t]",textContent) == 1)
                                {
                                    printf("%s\n", textContent);
                                }
                                sleep(seconds);
                            }
                        }
                    
            fclose(defaultFile);      
            fclose(contentFile);
     }
   }
   else
   {
     if(contentFile == NULL)
     {
       printf("\nFile does not exist. (Scanned file: %s)\n", fileName);
       fclose(contentFile);
     }
   }
}

fclose(orderFile);
printf("\n");

感谢 chux，它现在可以很好地工作，但还没有完全工作。

如果我有以下内容:

当前时间:15:00

订单.txt

file1.txt;5;15:01

file2.txt;6;15:02

file3.txt;3;15:03

当我运行程序时，会发生以下情况:

DEFAULT MESSAGE (text inside default.txt)

WAITS DIFF_TIME (CORRECTLY DONE)

SHOWS CONTENT FROM THE file1.txt

WAITS 5 SECONDS

X - SHOWS CONTENT FROM THE file2.txt (This is wrong, it should check again and if the time is 15:02 it will show, not 15:01. Which I assume it's because it is still reading as 15:01 on the timeValue and not 15:02, any idea why?)

WAITS UNTILL IT'S 15:02 (wrong)

SHOWS file3.txt (wrong)

WAITS UNTILL IT'S 15:03

ENDS (wrong as it should not end after waiting, it should end when file3.txt shows and waits for 3 seconds)

我需要的输出:

DEFAULT MESSAGE

waits diff_time

file1.txt content

waits 5 seconds

DEFAULT MESSAGE

waits diff_time

file2.txt content

waits 7 seconds

DEFAULT MESSAGE

waits diff_time

file3.txt content

waits 3 seconds

ENDS

如果我同时有两个文件，它也不能正常工作，例如:

订单.txt

file1.txt;5;15:01

file2.txt;6;15:01

file3.txt;3;15:02

它也打破了它。知道如何正确执行此操作吗？

Answer 1

正如@M Oehm 上面的评论，很明显编译器警告没有完全启用。建议启用它们 - 这会节省您的时间。

问题在于时间的比较和减法。

// Troublesome code
if(currentTime->tm_hour < hour && currentTime->tm_min < min) {
  diff_time = difftime(currentTime,timeValue);
  printf("%d - Or this?\n", diff_time);
  sleep(diff_time);
}

1. 比较好奇。通常这样的比较会是这样的形式

   if (h1 < h2 || (h1 == h2 && m1 < m2))
   

2. difftime 需要 2 个 time_t 参数，而不是 char timeValue[50] 和一个 struct tm .

3. 传递给 double difftime(time_t time1, time_t time0) 的值向后显示。结果是 time1 - time0。

改为推荐

    int current_hm = currentTime->tm_hour * 60 + currentTime->tm_min;
    int file_hm = hour * 60 + min;

    if (current_hm < file_hm) {
      unsigned diff_time = (file_hm - current_hm)*60u;
      printf("%u - Or this?\n", diff_time);
      sleep(diff_time);
    }

---

[编辑]简化方法。

    time_t now;
    time(&now);

    struct tm file_time_tm;
    file_time_tm = *localtime(&now);
    file_time_tm.tm_hour = hour;  // from file
    file_time_tm.tm_min = min; // from file
    file_time_tm.tm_sec = 0;
    file_time_tm.tm_isdst = -1;
    time_t filetime = mktime(&file_time_tm);

    double diff = difftime(filetime, now);  // filetime - now
    if (diff > 0) {
      sleep((unsigned) diff);
    }