c++ - 使用C在文本中搜索一个词，并显示该词后的信息

Question

假设我有一个这样的文本文件:

用户:约翰

设备:12345

日期:2012 年 12 月 12 日

编辑:

我有我的代码可以成功搜索一个词，并显示该词之后的信息。但是，当我尝试编辑代码以搜索 2 或 3 个词并在它们之后显示信息而不是仅显示 1 个词时，我无法让它工作。我曾尝试将代码添加到同一个 while 循环中，并为另一个词创建一个新的 while 循环，但两者都不起作用。一定有什么地方我做错了/没做。

请指教，谢谢!

这是我的代码:

 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 int main() {

char file[100];
char c[100];

printf ("Enter file name and directory:");
scanf ("%s",file);

    FILE * fs = fopen (file, "r") ;
    if ( fs == NULL )
    {
           puts ( "Cannot open source file" ) ;
           exit( 1 ) ;
    }

    FILE * ft = fopen ( "book5.txt", "w" ) ;
    if ( ft == NULL )
    {
           puts ( "Cannot open target file" ) ;
           exit( 1 ) ;
    }

while(!feof(fs)) {
   char *Data;
   char *Device;
   char const * rc = fgets(c, 99, fs);

   if(rc==NULL) { break; }

   if((Data = strstr(rc, "Date:"))!= NULL)
   printf(Data+5);

   if((Data = strstr(rc, "Device:"))!=NULL)
   printf(Device+6);
   }



    fclose ( fs ) ;
    fclose ( ft ) ;

return 0;

 }

Answer 1

好的，希望我这次能清除它。对不起，如果我有时会感到困惑，但我的英语不是最好的。

我将在评论中解释实现:

#define BUFFSIZE 1024
int main()....

char buff[BUFFSIZE];
char delims[] = " ";  /*Where your strtok will split the string*/
char *result = NULL;
char *device; /*To save your device - in your example: 12345*/
char *date; /*To save the date*/
int stop = 0;

fp = fopen("yourFile", "r");

while( fgets(buff, BUFFSIZE,fp) != NULL )  /*This returns null when the file is over*/
{
 result = strtok( buff, delims );   /*You just need to do reference to buff here, after this, strtok uses delims to know where to do the next token*/

   while(result != NULL){   /*Strtok returns null when finishes reading the given string*/
      if(strcmp(result,"Device")==0){   /*strcmp returns 0 if the strings are equal*/
         result = strtok(NULL, delims); /*this one gets the 12345*/
         device = (char*)malloc((strlen(result)+1)*sizeof(char)); /*Alocate the right amount of memory for the variable device*/
         strcpy(device, result); /*Now, device is "12345"*/
      }
       /*Here you do the same but for the string 'Date'*/
       if(strcmp(result,"Date")==0){   /*strcmp returns 0 if the strings are equal*/
         result = strtok(NULL, delims); /*this one gets the 12345*/
         date = (char*)malloc((strlen(result)+1)*sizeof(char)); /*Alocate the right amount of memory for the variable device*/
         strcpy(date, result); /*Now, device is "12/12/12"*/
      }
      /*And you can repeat the if statement for every string you're looking for*/
      result = strtok(NULL,delims);  /*Get the next token*/
   }
}

/*No strtok necessary here */

...

希望这对您有所帮助。