C language——to Replace a specified Line in a Text File

[root@localhost 桌面]# gedit tmp.c

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  1. // C Language to Replace a specified Line in a Text File

  3. #include <stdio.h>

  5. int main(void)
  6. {
  7.     FILE *fileptr1, *fileptr2;
  8.     char filechar[40];
  9.     char c;
  10.     int delete_line, temp = 1;

  12.     printf("Enter file name: ");
  13.     scanf("%s", filechar);

  15.     fileptr1 = fopen(filechar, "r");
  16.     //print the contents of file .
  17.     while ((c = getc(fileptr1)) != EOF)
  18.     {
  19.         printf("%c", c);
  20.     }

  22.     printf("\nEnter line number to be deleted and replaced: ");
  23.     scanf("%d", &delete_line);

  25.     //take fileptr1 to start point.
  26.     rewind(fileptr1);
  27.     //open tempinterm.txt in write mode
  28.     fileptr2 = fopen("tempinterm.txt", "w");

  30.     while ((c = getc(fileptr1)) != EOF)
  31.     {
  32.         //till the line to be deleted comes,copy the content to other
  33.         if (temp != delete_line) {
  34.             putc(c, fileptr2);
  35.             while ((c = getc(fileptr1)) != '\n') putc(c, fileptr2);
  36.             putc('\n', fileptr2);
  37.             temp++;
  38.         } else {
  39.             while ((c = getc(fileptr1)) != '\n');
  40.             //read and skip the line ask for new text
  41.             printf("Enter new text: ");

  43.             //flush the input stream
  44.             fflush(stdin);
  45.             getchar();    //delete blank line

  47.             while ((c = getchar()) != '\n') putc(c, fileptr2);
  48.             //take the data from user and place it in new file
  49.             putc('\n', fileptr2);
  50.             temp++;
  51.         }
  52.     }

  54.     fclose(fileptr1);
  55.     fclose(fileptr2);
  56.     remove(filechar);
  57.     rename("tempinterm.txt", filechar);
  58.     fileptr1 = fopen(filechar, "r");
  59.     //reads the character from file
  60.     //until last character of file is encountered
  61.     while ((c = getc(fileptr1)) != EOF)
  62.     {
  63.         printf("%c", c);
  64.     }
  65.     fclose(fileptr1);
  66.     return 0;
  67. }
[root@localhost 桌面]# gcc tmp.c -o tmp

[root@localhost 桌面]# ./tmp
Enter file name: hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

Enter line number to be deleted and replaced: 1
Enter new text: asdf
asdf
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
[root@localhost 桌面]#


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posted @ 2016-02-01 00:00  张同光  阅读(77)  评论(0)  编辑  收藏  举报