#include <stdio.h>
#define SIZE 99

void mean(const int answer[]);
void median(int answer[]);
void mode(int freq[], const int anser[]);
void bubbleSort(int a[]);
void printArray(const int a[]);

int main(void)
{
    int frequency[10] = {0};
    int 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(const int answer[])
{
    int j;
    int total = 0;
    printf("%s\n%s\n%s\n", "*********"," Mean ", "*********");
    for(j = 0; j < SIZE; 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, (double)total / SIZE);
        
}

void median(int answer[])
{
    printf("\n%s\n%s\n%s\n%s", "********", " Median", "*******", "The unsorted array of responses is");
 
    printArray(answer); /*在median函数里不是调用两次printArray函数吗，运行程序怎么才打印出一次printArray函数的呢?*/
    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 freq[], const int answer[])
{
    int rating;
    int j;
    int h;
    int largest = 0;
    int modeValue = 0;
    printf("\n%s\n%s\n%s\n",
        "********", " Mode" , "********");
    for(rating = 1; rating <= 9; rating++) {
        freq[rating] = 0;
    }
    for(j = 0; j < SIZE; j++) {
        ++freq[answer[j]];
    }
    printf("%s%11s%19s\n\n%54s\n%54s\n\n", "Response", "Frequency", "Histogram",
        "1        1        2        2", "5        0        5        0        5");
    for(rating = 1; rating <= 9; rating++) {
        printf("%8d%11d", rating, freq[rating]);
        if(freq[rating] > largest) {
            largest = freq[largest];
            modeValue = rating;
        }
        for(h = 1; h <= freq[rating]; h++) {
            printf("*");
        }
        printf("\n");
    }
    printf("The mode is the most frequent value.\n"
        "For this run the mode is %d which occurred"
        "%d times.\n", modeValue, largest);

}

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

    for(pass = 1; pass < SIZE; pass++) {
        for(j = 0; j < SIZE - 1; j++) {
            if(a[j] > a[j+1]) {
                hold = a[j];
                a[j] = a[j + 1];
                a[j + 1] = hold;
            }
        }
    }

}

void printArray(const int a[])
{
    int j;
    for(j = 0; j < SIZE; j++) {
        if(j % 20 == 0) {
            printf("\n");
        }
        printf("%2d", a[j]);
    }
}