Chapter-3/3-39.c

   1 /*C How to Program, 6/E, Deitel & Deitel.
   2
   3 Solution of exercise 3.39:
   4 (Counting 7s) Write a program that reads an integer and determines and prints
   5 how many digits in the integer are 7s.
   6
   7 Written by Juan Carlos Moreno (jcmhsoftware@gmail.com), 2023-02-11.*/
   8
   9 #include <stdio.h>
  10
  11 int main(void)
  12 {
  13     int number, digit, number2;
  14     int power_of_ten = 1000000000, counter = 0;
  15
  16     printf("Enter the number: ");
  17     scanf("%d", &number);
  18     number2 = number;
  19
  20     while (power_of_ten >= 1)
  21     {
  22         digit = number2 / power_of_ten;
  23         number2 = number2 % power_of_ten;
  24         power_of_ten = power_of_ten / 10;
  25
  26         if (digit == 7)
  27         {
  28             counter++;
  29         }
  30     }
  31     printf("There are %d 7s in the integer %d.\n", counter, number);
  32
  33     return 0;
  34 }