这个编程技巧别说我没告诉你

//来源：公众号【编程珠玑】
#include <stdio.h>
enum KID_STATUS
{
    SLEEP = 0,
    WAKE = 1,
    INVALID = 2
};
enum KID_ACTION
{
    SMILE = 0,
    EAT = 1,
    PEE = 2
};
/*孩子当前状态*/
static int nowStatus = WAKE;

/*孩子行为*/
int smile(int status)
{
    printf("kid smile\n");
    return status;
}
int eat(int status)
{
    printf("kid eat\n");
    return SLEEP;
}
int pee(int status)
{
    printf("kid pee\n");
    return WAKE;
}
/*孩子产生某个行为*/
void execute(int action)
{
    int nextStatus;
    /*醒着时的行为*/
    if(WAKE == nowStatus)
    {
        switch(action)
        {
            case SMILE:
            {
                nextStatus = smile(nowStatus);
                break;
            }
            case EAT:
            {
                nextStatus = eat(nowStatus);
                break;
            }
            case PEE:
            {
                nextStatus = pee(nowStatus);
                break;
            }
            default:
                printf("unknow action when wake %d\n",action);
                nextStatus = nowStatus;
                break;
        }
    }
    /*睡着时的行为*/
    else if(SLEEP == nowStatus)
    {
        switch(action)
        {
            case SMILE:
            {
                nextStatus = smile(nowStatus);
                break;
            }
            casePEE:
            {
                nextStatus = pee(nowStatus);
                break;
            }
            default:
                printf("unknow action when sleep %d\n",action);
                nextStatus = nowStatus;
                break;
        }
    }
    else
    {
        printf("unknow action\n");
    }
    nowStatus = nextStatus;
    printf("next status is %d\n",nowStatus);
}
int main(void)
{
    nowStatus = SLEEP;
    execute(EAT);
    return 0;
}

//来源：公众号【编程珠玑】地址：https://www.yanbinghu.com
#include <stdio.h>
/*省略枚举定义和函数定义，与前面相同*/
typedef int (*Handler)(int);//函数指针
/*用于处理某种状态的行为*/
typedef struct Act_Handler
{
    int action;
    Handler handler;
}Act_Handler;
/*某种状态的处理集*/
typedef struct Stat_Handler
{
    int status;
    int actNum;
    Act_Handler *actHandler;
}Stat_Handler;
/*sleep状态行为处理*/
Act_Handler sleepHandler[] = 
{
    {SMILE,smile},
    {PEE,pee}
};
/*wake状态行为处理*/
Act_Handler weakHandler[] = 
{
    {SMILE,smile},
    {PEE,pee},
    {EAT,eat}
};
/*状态处理*/
static Stat_Handler statHandler[] = 
{
    {SLEEP,sizeof(sleepHandler)/sizeof(Act_Handler),sleepHandler},
    {WAKE,sizeof(weakHandler)/sizeof(Act_Handler),weakHandler},
};
static int statSize = sizeof(statHandler)/ sizeof(Stat_Handler);
void execute(int action)
{
    if(nowStatus >= statSize)
    {
        printf("unknow status\n");
        return;
    }
    printf("now status is %d,action %d\n",nowStatus,action);
    int nextStatus = nowStatus;
    Act_Handler *actHandler = statHandler[nowStatus].actHandler;
    int actNum = statHandler[nowStatus].actNum;
    int actIdx = 0;
    /*遍历指定状态下的行为集，找到对应的行为*/
    for(actIdx = 0;actIdx < actNum;actIdx++)
    {
        if(actHandler[actIdx].action == action)
        {
            nextStatus = (actHandler[actIdx].handler)(action);
            break;
        }
    }
    if(actIdx == actNum)
    {
        printf("did find action %d in status %d\n",action,nowStatus);
    }
    nowStatus = nextStatus;
    printf("next status is %d\n",nowStatus);
}
int main(void)
{
    nowStatus = WAKE;
    execute(EAT);
    return 0;
}