/*
 *          File: hw2-histogram.c
 *        Author: rpruim
 *         Class: cs113 fall 97
 *    Assignment: hw2
 * Last modified: 16 sep 97
 * -----------------------------------------------------
 *
 * OVERVIEW:
 * =========
 * This program requests the user to input a sequence of integers 
 * (terminated by a sentinel value of the user's choice) and then produces
 * a histogram of the data.  The user can specify the range for the 
 * histogram as well as the size of the subdivisions ("step size").
 *
 * Algorithm Notes:  
 * ================
 * This program makes use of utility functions from hw2-util and hw2-stats.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include "genlib.h"
#include "simpio.h"
#include "hw2-util.h"
#include "hw2-stats.h"

void DisplayInstructions(void);
int GetHistVals(int sentinel, int *loPtr, int *hiPtr, int *stepPtr);

/* Main Program */

int main()
{
  int sentinel;		/* used to indicate end of data */
  int *scores;		/* array of scores for histogram */
  int size;		/* size of array */
  int lo, hi, step;	/* data for histogram shape */
  int error;		/* indicates histogram values */

  DisplayInstructions();

  printf("Enter sentinel value:  "); 
  sentinel = GetInteger();
  printf("\nNow enter values separated by returns and ended with %d.\n\n", 
		sentinel);
  scores = GetDynamicIntArray(sentinel, "", &size);

  while(TRUE) {
    error = GetHistVals(sentinel, &lo, &hi, &step);
    if (error != 0) {break;}
    printf("\n\n");
    PrintHistogram(scores, size, lo, hi, step);
    printf("\n\n");
  }
 

  exit(0);	/* let the OS know that the program terminated normally */

}		/* end main */



/*
 * Function: DisplayInstructions
 * Usage: DisplayInstructions();
 * -----------------------------
 * This function prints to standard output instructions for the user.
 */

void DisplayInstructions()
{
  printf("WELCOME TO HW2-HISTOGRAM!!\n\n");
  printf("This program will display a histogram for a list of integers\n");
  printf("which you provide.\n\n");
  printf("You will be asked to enter a sentinel value.  This should be\n");
  printf("some integer which does not occur in the data set, and is used\n");
  printf("to indicate the end of the data.  Then you will enter scores.\n");
  printf("Once the sentinel value has been entered, you will be asked to\n");
  printf("provide the upper and lower bounds for the histogram as well as\n");
  printf("the size of each subinterval.  Then the program will generate\n");
  printf("the desired histogram.  Multiple histograms can be displayed for\n");
  printf("the same data.\n\n");

}		/* end DisplayInstructions() */

int GetHistVals(int sentinel, int *loPtr, int *hiPtr, int *stepPtr)
{

  printf("Low value in histogram (%d to quit): ", sentinel);
  *loPtr = GetInteger();
  if (*loPtr == sentinel) {return (-1);}
  
  printf("High value in histogram (%d to quit): ", sentinel);
  *hiPtr = GetInteger();
  if (*hiPtr == sentinel || *hiPtr < *loPtr) {return (-2);}

  printf("Step size: ");
  *stepPtr = GetInteger();
  if (*stepPtr < 1) {return (-5);}

  return(0);
}