// File: curve.cxx
// Program to read scores in a class and print
// how many students fall in each ten-point category
#include <fstream>
#include <iostream>

const int MANY_CATS = 11;
const int CATEGORY_SIZE = 10;
const char GRADE_FILE[] = "grades.txt";

//----------------------------------------------------
// Prototypes

void read_scores(int cat[]);
// This function sets all categories to zero, and then
// reads the grade file; each time it reads a score,
// it figures out which category that score is in
// and adds one to the category.

void print_results(int cat[]);
// Print a table of how many students are in each
// category.
    
//----------------------------------------------------



//----------------------------------------------------
int main( )
{
    int categories[MANY_CATS];

    read_scores(categories);
    print_results(categories);

    return 0;
}
//----------------------------------------------------



//----------------------------------------------------
void read_scores(int cat[])
{
    int i;              // Loop control variable
    ifstream grade_in;  // The grade file
    int next;           // A grade from the grade file
    int category;       // The category for the grade
    
    for (i = 0; i < MANY_CATS; i++)
    {
	cat[i] = 0;
    }

    grade_in.open(GRADE_FILE);
    while (grade_in && grade_in.peek( ) != EOF)
    {
	grade_in >> next;
	grade_in.ignore( );
        category = next / CATEGORY_SIZE;
        if ((0 <= category) && (category < MANY_CATS)) 	
	{
	    cat[category]++;
	}
	else
	{
	    cerr << "Illegal input: "
		 << next
		 << endl;
	}
    }
}



//----------------------------------------------------
void print_results(int cat[])
{
    int i;

    for (i = 0; i < MANY_CATS; i++)
    {
	if (cat[i] > 0)
	{
	    cout << "Number of scores in range of "
		 << i*CATEGORY_SIZE
		 << " to "
		 << i*CATEGORY_SIZE + CATEGORY_SIZE - 1
		 << ": "
		 << cat[i]
		 << endl;
	}
    }
}