Shuffle Array Algorithm

shuffle_array.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define SIZE 10

void ShuffleArray_Fisher_Yates(char* arr, const int len)
{
    int i = len, j;
    char temp;
    if ( i == 0 ) return;
    while ( --i ) {
        j = rand() % (i+1);
        temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
}

void ShuffleArray_General(char* arr, int len)
{
    const int suff_time = len;
    for(int idx=0; idx<suff_time; idx++) {
        int i = rand() % len;
        int j = rand() % len;
        char temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
}

void printArray(char a[], const int len)
{
    int i;
    for (i = 0; i < len; ++i)
        printf("%c ", a[i]);
    printf("\n");
}

void log_array(char a[], int log[][SIZE], const int len)
{
    int i, j;
    for (i = 0; i < SIZE; ++i)
    {
        j = a[i] - 'A';
        ++log[j][i];
    }
}

void print_logger(int log[][SIZE], const int len)
{
    int i, j;
    int min = 2100000000;
    int max = 0;
    printf("- | ");
    for (i = 1; i <= len; ++i)
    {
        printf("%7d ", i);
    }
    printf("\n");

    for (i = 0; i <= 88; ++i)
    {
        if (i == 2)
            printf("+");
        else
            printf("-");
    }
    printf("\n");

    for (i = 0; i < len; ++i)
    {
        printf("%c | ", 'A' + i);
        for (j = 0; j < len; ++j)
        {
            printf("%7d ", log[i][j]);
            if (max < log[i][j])
                max = log[i][j];
            if (min > log[i][j])
                min = log[i][j];
        }
        printf("\n");
    }
    printf("\n");
    printf("min: %d max: %d\n\n", min, max);
}

void test(void (*shuffle_array)(char *, const int))
{
    srand(time(0));
    int i, j;
    int log[SIZE][SIZE];

    char a[SIZE];
    for (i = 0; i < SIZE; ++i)
        a[i] = 'A' + i;

    for (i = 0; i < SIZE; ++i)
    {
        for (j = 0; j < SIZE; ++j)
            log[i][j] = 0;
    }

    for (i = 0; i < 1000000; ++i)
    {
        (*shuffle_array)(a, SIZE);
        log_array(a, log, SIZE);
    }
    print_logger(log, SIZE);
}

int main()
{
    int i;
    for (i = 0; i < 20; ++i)
        test(ShuffleArray_General);

    for (i = 0; i < 20; ++i)
        test(ShuffleArray_Fisher_Yates);
}