/* This program introduces the topic of survey data analysis. 
   It computes the mean, median, and  mode of the data */
#include <stdio.h>
#define SIZE 99

void mean(int []);
void median(int []);
void mode(int [], int []);
void bubbleSort(int[]);
void printArray(int[]);

main()
{
   int frequency[10] = {0},
       response[SIZE] = {6, 7, 8, 9, 8, 7, 8, 9, 8, 9,
                         7, 8, 9, 5, 9, 8, 7, 8, 7, 8,
                         6, 7, 8, 9, 3, 9, 8, 7, 8, 7,
                         7, 8, 9, 8, 9, 8, 9, 7, 8, 9,
                         6, 7, 8, 7, 8, 7, 9, 8, 9, 2,
                         7, 8, 9, 8, 9, 8, 9, 7, 5, 3,
                         5, 6, 7, 2, 5, 3, 9, 4, 6, 4,
                         7, 8, 9, 6, 8, 7, 8, 9, 7, 8,
                         7, 4, 4, 2, 5, 3, 8, 7, 5, 6,
                         4, 5, 6, 1, 6, 5, 7, 8, 7};
   mean(response);
   median(response);
   mode(frequency, response);
   return 0;
}

void mean(int answer[])
{
   int j, total = 0;

   printf("%s\n%s\n%s\n", "********", "  Mean", "********");

   for (j = 0; j <= SIZE - 1; j++)
      total += answer[j];

   printf("The mean is the average value of the data\n"
          "items. The mean is equal to the total of\n"
          "all the data items divided by the number\n"
          "of data items (%d). The mean value for\n"
          "this run is: %d / %d = %.4f\n\n",
          SIZE, total, SIZE, (float) total / SIZE);
}

void median(int answer[])
{
   printf("\n%s\n%s\n%s\n%s", 
          "********", " Median", "********", 
          "The unsorted array of responses is");

   printArray(answer);
   bubbleSort(answer);
   printf("\n\nThe sorted array is");
   printArray(answer);
   printf("\n\nThe median is element %d of\n"
          "the sorted %d element array.\n"
          "For this run the median is %d\n\n",
          SIZE / 2, SIZE, answer[SIZE / 2]);
}

void mode (int f[], int r[])
{

   int i,j;

   for (i=0;i<100;i++)
   f[r[i]]++;

   for (i=0; i<10; i++)
   {
     printf("response=%d frequency=%2d ",i,f[i]);
     for (j=0; j<f[i]; j++)
       printf("*");
     printf("\n");
   }

}

void bubbleSort(int a[])
{
   int pass, j, hold;

   for (pass = 1; pass <= SIZE - 1; pass++)

      for (j = 0; j <= SIZE - 2; j++)

         if (a[j] > a[j+1]) {
            hold = a[j];
            a[j] = a[j+1];
            a[j+1] = hold;
         }
}

void printArray(int a[])
{
   int j;

   for (j = 0; j <= SIZE - 1; j++) {

      if (j % 20 == 0)
         printf("\n");

      printf("%2d", a[j]);
   }
}