ungetc example in C

Header file:

    stdio.h

Synopsis:

     int ungetc(int ch, FILE *stream);

Description:

     It pushes character ch back onto the given stream.  Returns character ch on success, EOF on failure.

ungetc function C example:

  #include<stdio.h>

  #include<string.h>

  int main() {

        char str[100], ch;

        FILE *fp;

        int i = 0;

        fp = fopen("mastering-c.txt", "r");

        if (fp == NULL) {

                printf("Error in opening the file\n");

                return;

        }

        while ((ch = getc(fp)) != EOF)  {

                if (i < 10)

                        ungetc('#', fp);  // pushing '#' back to the stream fp

                putchar(ch);

                i++;

        }

        fclose(fp);

        return 0;

  }

  Output:

  jp@jp-VirtualBox:~/cpgms/exp$ cat mastering-c.txt
  Hello world
  This is puts example program in C
  Thanks for visiting our blog
  jp@jp-VirtualBox:~/cpgms/exp$ gcc ungetc.c
  jp@jp-VirtualBox:~/cpgms/exp$ ./a.out
  H##########ello world
  This is puts example program in C
  Thanks for visiting our blog