//*****************************************************************
// R. A. Hillyard
// histogram.cpp
// March 2001
//
//  Accept exam scores (between 0 and 100) from the user. The end-of-input will
//  be signalled by the value -1. Display a histogram of those scores by printing
//  the number of scores between 0 & 9, between 10 & 19, between 20 & 29, etc.
//    Method:
//      range[0] holds the number of scores between 0 and 9
//      range[1] holds the number of scores between 10 and 19
//                      |
//                      |
//                      |
//      range[9] holds the number of scores between 90 and 99
//      range[10] holds the number of 100s
//*****************************************************************

#include <iostream>

using namespace std;

const int NUM_RANGES = 11;

int main()
  {
  int score;              //variable for user input
  int range[NUM_RANGES];  //range[k] holds the number of scores seen
                          //so far between 10*k and 10*k + 9

  //initialize the counters
  for (int k = 0; k < NUM_RANGES; k++)
    range[k] = 0; 

  //get input
  cout << "Enter scores --- (-1 to quit)" << endl;
  do
   {
    cout << "> ";
    cin >> score;
    if (score == -1)
      break;
    range[score / 10]++;   //increment the counter
    } while (true);

  //print results
  cout << endl << "Histogram of scores:" << endl;
  for (int k = 0; k < NUM_RANGES-1; k++)
    cout << 10*k << " to " << 10*k + 9 << " : " << range[k] << endl;

  cout << "100      : " << range[10] << endl;
  return 0;
  }
//************************Program Output***************************
Enter scores --- (-1 to quit)
> 87
> 55
> 44
> 33
> 98
> 12
> 7
> 34
> 33
> 66
> 77
> 88
> 99
> 100
> 100
> 0
> 34
> 94
> 87
> -1

Histogram of scores:
0 to 9 : 2
10 to 19 : 1
20 to 29 : 0
30 to 39 : 4
40 to 49 : 1
50 to 59 : 1
60 to 69 : 1
70 to 79 : 1
80 to 89 : 3
90 to 99 : 3
100      : 2