Ποια είναι η λειτουργία του ακόλουθου προγράμματος:

            #include <stdio.h>

            main()

            {

                        FILE *f1;

                        char get_char;

                        int sum_b=0;

                        f1=fopen("file1.dat","r");

                        while (get_char!=EOF)

                        {

                                    get_char=getc(f1);

                                    if (get_char = = 'b') sum_b++;

                        }

                        fclose(f1);

                        printf("\nNumber of 'b'’s:%d",sum_b);

            }