享元模式看上去有點玄乎，但是其實也沒有那麼複雜。我們還是用示例說話。比如說，大家在使用電腦的使用應該少不了使用WORD軟體。使用WORD呢， 那就少不了設定模板。什麼模板呢，比如說標題的模板，正文的模板等等。這些模板呢，又包括很多的內容。哪些方面呢，比如說字型、標號、字距、行距、大小等等。

typedef struct _Font
{
    int type;
    int sequence;
    int gap;
    int lineDistance;

    void (*operate)(struct _Font* pFont);

}Font;

typedef struct _FontFactory
{
    Font** ppFont;
    int number;
    int size;

    Font* GetFont(struct _FontFactory* pFontFactory, int type, int sequence, int gap, int lineDistance);
}FontFactory;
 

    這裡的GetFont即使對當前的Font進行判斷，如果Font存在，那麼返回；否則建立一個新的Font模式。

Font* GetFont(struct _FontFactory* pFontFactory, int type, int sequence, int gap, int lineDistance)
{
    int index;
    Font* pFont;
    Font* ppFont;

    if(NULL == pFontFactory)
        return NULL;

    for(index = 0; index < pFontFactory->number; index++)
    {
        if(type != pFontFactory->ppFont[index]->type)
            continue;

        if(sequence != pFontFactory->ppFont[index]->sequence)
            continue;

        if(gap != pFontFactory->ppFont[index]->gap)
            continue;

        if(lineDistance != pFontFactory->ppFont[index]->lineDistance)
             continue;

        return pFontFactory->ppFont[index];
    }    

    pFont = (Font*)malloc(sizeof(Font));
    assert(NULL != pFont);
    pFont->type = type;
    pFont->sequence = sequence;
    pFont->gap = gap;
    pFont->lineDistance = lineDistance;

    if(pFontFactory-> number < pFontFactory->size)
    {
        pFontFactory->ppFont[index] = pFont;
        pFontFactory->number ++;
        return pFont;
    }

    ppFont = (Font**)malloc(sizeof(Font*) * pFontFactory->size * 2);
    assert(NULL != ppFont);
    memmove(ppFont, pFontFacoty->ppFont, pFontFactory->size);
    free(pFontFactory->ppFont);
    pFontFactory->size *= 2;
    pFontFactory->number ++;
    ppFontFactory->ppFont = ppFont;
    return pFont;       
}