Question

嗨，我是一个begginer c程序员，我正在尝试制作一个过滤器，该过滤器应该根据其他变量更改变量，但它似乎不会因某种原因更改变量g1。我真的得到任何帮助，因为我现在被困在这里。感谢

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


int main(void)
{
    int car;
    int g1;
    int g2;
    int sel1;
    unsigned int iseed = (unsigned int)time(NULL);          
    srand (iseed);
    g1 = 0;
    car = rand() % 3 + 1;
    printf("%d\n",car);

    printf("select a door beetween 1 and 3\n ");
    scanf ("%d",&sel1);
    if (sel1 < 0)
    {
        printf("Invalid selection!\n");
        return 0;
    }
    if (sel1 > 3)
    {
        printf("Invalid selection!\n");
        return 0;
    }

    if (sel1 == 1)
    {   
        if(car == 1)
        {
            g1 = 2;
            g2 = 3;
        }   
        if (car == 2);
        {
            g1 = 3;
            g2 = 1;
        }
        if (car == 3);
        {
            g1 = 2;
            g2 = 1;
        } 
    }

    if (sel1 == 2)
    {   
        if(car == 1)
        {
            g1 = 3;
            g2 = 2;
        }   
        if (car == 2);
        {
            g1 = 1;
            g2 = 3;
        }
        if (car == 3);
        {
            g1 = 1;
            g2 = 2;
        } 
    }

        if (sel1 == 3)
    {   
        if(car == 1)
        {
            g1 = 2;
            g2 = 3;
        }   
        if (car == 2);
        {
            g1 = 1;
            g2 = 3;
        }
        if (car == 3);
        {
            g1 = 1;
            g2 = 2;
        } 
    }

    printf("Behind door %d is a goat\n",g1);



    return 0;
}

显然我没有足够的细节所以忽略这个我只是添加一些随机的细节。在小学数学中，变量是表示数字的字母字符，称为变量的值，它是任意的，未完全指定的或未知的。

Answer 1

首先，正如@BLUEPIXY建议的那样，您应该删除;。

我会将前两个sel1条件更改为仅设置一个，如下所示：

if (sel1 < 1 || sel1 > 3)
    printf("Invalid selection!\n");

然后我会使用switch个案和if声明：

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


int main(void)
{
    int car;
    int g1;
    int g2;
    int sel1;
    unsigned int iseed = (unsigned int)time(NULL);
    srand(iseed);
    g1 = 0;
    car = rand() % 3 + 1;
    printf("Car= %d\n", car);

    printf("Select a door beetween 1 and 3:\n");
    scanf("%d", &sel1);


    if (sel1 < 1 || sel1 > 3)
        printf("Invalid selection!\n");

    switch (sel1)
    {
    case 1:
        if (car == 1)
        {
            g1 = 2;
            g2 = 3;
        }
        else if (car == 2)
        {
            g1 = 3;
            g2 = 1;
        }
        else if (car == 3)
        {
            g1 = 2;
            g2 = 1;
        }

        break;

    case 2:
        if (car == 1)
        {
            g1 = 3;
            g2 = 2;
        }
        else if (car == 2)
        {
            g1 = 1;
            g2 = 3;
        }
        else if (car == 3)
        {
            g1 = 1;
            g2 = 2;
        }
        break;

    case 3:
        if (car == 1)
        {
            g1 = 2;
            g2 = 3;
        }
        else if (car == 2)
        {
            g1 = 1;
            g2 = 3;
        }
        else if (car == 3)
        {
            g1 = 1;
            g2 = 2;
        }
        break;
    }


    printf("Behind door, %d is a goat\n", g1);


    getchar();
    getchar();  

    return 0;   
}

示例：

Answer 2

我注意到你没有说明sel1==0会发生什么你为sel1>3和sel1==3以及sel1==2和sel1==1以及sel1<0加了引号，但你没有说明如果sel1==0我认为g1是什么如果sel1为0，则不更改，否则更改也许你应该在输入sel1时放一个空格，如下所示

scanf ("%d ",&sel1);

并在条件;和if(car==2)

之后移除if(car==3)

变量不变c

2 个答案: