有時候我們需要刪除檔案的某一行，來更新檔案，在這我個人擴充套件了一個函式，以刪除指定條件的行。

 1 static void UpdateHistoryFile(void)
 2 {
 3     FILE *fin,*fout;
 4     int counter = 1;
 5     STest test;
 6  
 7     do
 8     {
 9         fin=fopen("test.txt","r");
10         fout=fopen("t.tmp","w");
11  
12         while(readHistoryFile(fin, &test) != EOF)
 
13         {
14             if (test.b == 20160516) // to add the judgement case.
15             {
16                 printf("test.b < 20160516\n");
17             }
18             else
19             {
20                 test.a = counter;
21                 writeHistoryFile(fout, test);
22                 counter++;
 
23             }
24         }
25         
26         fclose(fin);
27         fclose(fout);
28  
29         remove("test.txt");
30         rename("t.tmp","test.txt");
31     }while(0);
32     
33     return;
34 }