Strategy_Exercise.c

Go to the documentation of this file.

 
 
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
 
#include "Strategy_SortStrategy.h"
 
#include "Strategy_Exercise.h"
 
 
//-----------------------------------------------------------------------------
 
static void Sort_Entries(const EntryInformation* entries, size_t numEntries, int* sortIndices, SortStrategy* sortStrategy)
{
    if (entries != NULL && sortIndices != NULL && sortStrategy != NULL)
    {
        for (size_t leftIndex = 0; leftIndex < numEntries - 1; leftIndex++)
        {
            for (size_t rightIndex = leftIndex + 1; rightIndex < numEntries; rightIndex++)
            {
                bool swapEntries = sortStrategy->compareFunction(&entries[sortIndices[leftIndex]], &entries[sortIndices[rightIndex]]);
                if (sortStrategy->reversedSort)
                {
                    swapEntries = !swapEntries;
                }
                if (swapEntries)
                {
                    int tempIndex = sortIndices[leftIndex];
                    sortIndices[leftIndex] = sortIndices[rightIndex];
                    sortIndices[rightIndex] = tempIndex;
                }
            }
        }
    }
}
 
static void Display_Entries(const EntryInformation* entries, size_t numEntries, int* sortIndices, SortStrategy* sortStrategy)
{
    if (entries != NULL && sortIndices != NULL)
    {
        // This is a tabular display, making it easier to follow the sorted data.
        printf("    Sort strategy: %s (order = %s)\n", sortStrategy->name, sortStrategy->reversedSort ? "Descending" : "Ascending");
        printf("      %-6s %3s %3s\n", "Name", "Age", "Height");
        printf("      %6s %3s %3s\n", "------", "---", "------");
        for (size_t index = 0; index < numEntries; index++)
        {
            const EntryInformation* entry = &entries[sortIndices[index]];
            printf("      %-6s %3d %3d\"\n", entry->Name, entry->Age, entry->Height);
        }
    }
}
 
//=============================================================================
//=============================================================================
static EntryInformation entries[] =
{
    // Name, age, height (in inches)
    { "Ronnie", 19, 84 },
    { "Elaine", 29, 71 },
    { "Jack", 20, 81 },
    { "Myra", 35, 78 },
    { "Fred", 18, 88 },
};
 
 
//=============================================================================
//=============================================================================
 
// ! [Using Strategy in C]
void Strategy_Exercise(void)
{
    printf("\nStrategy Exercise\n");
 
    size_t numEntries = sizeof(entries) / sizeof(entries[0]);
    int* sortIndices = malloc(numEntries * sizeof(int)); // These are sortable indices into entries
    if (sortIndices != NULL)
    {
        for (int index = 0; index < (int)numEntries; index++)
        {
            sortIndices[index] = index;
        }
 
        SortStrategy sortStrategy = { 0 };
 
        SortStrategy_Initialize(&sortStrategy, Sort_ByName, false);
        Sort_Entries(entries, numEntries, sortIndices, &sortStrategy);
        Display_Entries(entries, numEntries, sortIndices, &sortStrategy);
 
        SortStrategy_Initialize(&sortStrategy, Sort_ByAge, false);
        Sort_Entries(entries, numEntries, sortIndices, &sortStrategy);
        Display_Entries(entries, numEntries, sortIndices, &sortStrategy);
 
        SortStrategy_Initialize(&sortStrategy, Sort_ByHeight, true);
        Sort_Entries(entries, numEntries, sortIndices, &sortStrategy);
        Display_Entries(entries, numEntries, sortIndices, &sortStrategy);
 
        free(sortIndices);
    }
    else
    {
        printf("  Error!  Out of memory creating array of indices to sort on!\n");
    }
 
    printf("  Done.\n");
}
// ! [Using Strategy in C]