Question

请查看以下代码

#include <iostream>
#include <stdlib.h>
#include <ctime>

using namespace std;

int main()
{
    enum Movement{STAND=1,WALK,RUN,CRAWL};

    srand(time(0));
    Movement state = (Movement)(1+rand()%4);

    for(int i=0;i<10;i++)
    {

    cout << state << endl;

    switch(state)
    {
        /*Here the logic is,
         * 
         * 1. From stand, he can walk or crawl
           2. From Walk, he can stand or run
           3. From Run, he can walk
           4. From Crawl, he can stand
         */

        case STAND: 
            cout << "You can walk or crawl" << endl;        
            while(state==WALK || state==CRAWL)
            {
                state = (Movement)(1+rand()%4);
            }
            break;


        case WALK: 
            cout << "You can stand or run" << endl;
            while(state==STAND || state==RUN)
            {
                state = (Movement)(1+rand()%4);
            }
            break;


        case RUN: 
            cout << "You can walk" << endl;
            while(state==WALK)
            {
                state = (Movement)(1+rand()%4);
            }
            break;

        default: 
            cout << "You can stand" << endl;
            while(state==STAND)
            {
                state = (Movement)(1+rand()%4);
            }

    }

    }
}

我使用随机，并期望基于给定条件的随机结果。但我得到的结果如下。

2
You can stand or run
2
You can stand or run
2
You can stand or run
2
You can stand or run
2
You can stand or run
2
You can stand or run
2
You can stand or run
2
You can stand or run
2
You can stand or run
2
You can stand or run

这是为什么？我也试过do..while循环。一点也不好。什么都没有检查我在案件陈述中给出的条件。请帮忙。

Answer 1

将你的while循环翻转为do-while。表达式对于检查也是无效的（除非您的意图与文本不匹配）。根据消息，状态为：

Stand ==> (Walk || Crawl)
Walk  ==> (Stand || Run)
Run   ==> (Walk)
Crawl ==> (Stand)

因此需要将这些部分更改为

在检查之前生成新的随机数。和..
在达到有效产品之前不要离开。

后一部分对于Run和Crawl状态很重要。因为它们只能产生一个有效的结果状态，所以旋转rand（）调用寻找该值是没有意义的。只需设置新状态并再次循环。

关于上述（2）：

    case WALK: 
        cout << "You can stand or run" << endl;
        while(state==STAND || state==RUN)
        {
            state = (Movement)(1+rand()%4);
        }
        break;

...变为

    case WALK: 
        cout << "You can stand or run" << endl;
        do {
            state = (Movement)(1+rand()%4);
        } while(state!=STAND && state!=RUN);
        break;

关于运行和抓取状态：

    case RUN: 
        cout << "You can walk" << endl;
        state = WALK;
        break;

    default: // CRAWL 
        cout << "You can stand" << endl;
        state = STAND;
        break;

这让你再检查一下，我留给你了。

Answer 2

解决方案：将Movement state = (Movement)(1+rand()%4);移至for循环。

更正后的代码：

#include <iostream>
#include <stdlib.h>
#include <ctime>

using namespace std;

int main()
{
    enum Movement{STAND=1,WALK,RUN,CRAWL};
    srand(time(0));

    for(int i=0;i<10;i++)
    {

        Movement state = (Movement)(1+rand()%4);

        cout << state << endl;

        switch(state)
        {
            /*Here the logic is,
             * 
             * 1. From stand, he can walk or crawl
               2. From Walk, he can stand or run
               3. From Run, he can walk
               4. From Crawl, he can stand
             */

            case STAND: 
                cout << "You can walk or crawl" << endl;        
                while(state==WALK || state==CRAWL)
                {
                    state = (Movement)(1+rand()%4);
                }
                break;


            case WALK: 
                cout << "You can stand or run" << endl;
                while(state==STAND || state==RUN)
                {
                    state = (Movement)(1+rand()%4);
                }
                break;


            case RUN: 
                cout << "You can walk" << endl;
                while(state==WALK)
                {
                    state = (Movement)(1+rand()%4);
                }
                break;

            default: 
                cout << "You can stand" << endl;
                while(state==STAND)
                {
                    state = (Movement)(1+rand()%4);
                }

        }

    }

    return 0;
}

输出：

3
You can walk
1
You can walk or crawl
2
You can stand or run
1
You can walk or crawl
2
You can stand or run
3
You can walk
4
You can stand
2
You can stand or run
2
You can stand or run
4
You can stand

Press any key to continue

Answer 3

您还可以在状态机中计算下一步：

...

case STAND:
    cout << "You can walk or crawl" << endl;
    state = rand()%2 ? WALK : CRAWL;
    break;

...

Answer 4

无论你做什么，使用常量种子的C中的

rand（）函数总是倾向于给出相同的“随机”值。

更好的方法是编写自己的RandomGenerator函数并使用它

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

int RandomGenerator(int min, int max) // Generate min < random int < max
{
  int randNum;
  srand(rand()*time(NULL));
  randNum = rand() % max + min;
  // printf(" Random number is %d \n", randNum);
  return randNum;
}

同时移动Movement state = (Movement)(1+rand()%4); for循环内的{{1}}

再次随机化的问题

4 个答案: