getchar() 和 scanf("%c",'name_of_variable') 的区别？

Question

我编写了一个 C 程序，它被认为是一个名为“刀石纸”的游戏。其中刀战胜了纸，石战胜了刀，纸战胜了石。我想通过提示用户在某些点输入 y(es) 或 n(o) 来使其用户友好。

但是，当我使用 scanf("%c",choice) 来存储用户的选择时，程序会表现得“有趣”或自动循环，但当我使用 getchar() 时可以完美运行。我想知道是不是这样。游戏代码如下。

要点是：

scanf("%c",&mainexit);
/*getchar();
mainexit=getchar();*/

和

scanf("%c",&exit);
/*getchar();
exit=getchar();*/  

游戏：

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

int main()
{
char mainexit;
do
{
int choice;
char exit;
printf("Welcome To StoneKnifePaper!!!!! \n");
a:
printf("Pick One Option.(Enter integers)\n");
b:
printf(" 1.Stone. \n 2.Knife. \n 3.Paper. \n 4.Exit. \n GoodLuck! :) \n");
scanf("%d",&choice);
if(choice <1 || choice>4)
{
    printf("Wrong Choice!!! Try Again. \n");
    goto b;
}
else if ( choice == 4)
{
    c:
    printf("Are You Sure You Want To Quit? \n [y/n] \n");
    scanf("%c",&exit);
    /*getchar();
    exit=getchar();*/      
    if (exit == 'Y' || exit == 'y')
    {
    return 0;
    }
    else if (exit == 'N' || exit == 'n')
    {
        goto a;
    }
    else if (exit != 'N' || exit!= 'n' || exit != 'Y' || exit != 'y')
    {
        printf("Wrong Entry. (Please Enter 'y' or 'n') \n");
        goto c;
    }
}
else if (choice >= 1 && choice <=3)
{
    int randomnumber = rand()%3 +1;
    if(choice==1 && randomnumber == 2)
    {
        printf("Congratulations!! Player has Won!! Stone Blunts Knife.");
    }
    else  if(choice==2 && randomnumber == 3)
    {
        printf("Congratulations!! Player has Won!! Knife Cuts Paper.");
    }
    else  if(choice==3 && randomnumber == 1)
    {
        printf("Congratulations!! Player has Won!! Paper wraps Stone.");
    }
    else  if(choice==2 && randomnumber == 1)
    {
        printf("Computer has won!! Stone Blunts Knife.");
    }
    else  if(choice==3 && randomnumber == 2)
    {
        printf("Computer has won!! Knife Cuts Paper.");
    }
    else  if(choice==1 && randomnumber == 3)
    {
        printf("Computer has won!! Paper Wraps Stone.");
    }
    else  if(choice == randomnumber)
    {
        printf("It's a draw!");
    }
}
else
{
    printf("Wrong Choice!!! Try Again. \n");
    goto b;
}
printf("\n Play Game Again? Try Your luck. \n [y/n] ");
scanf("%c",&mainexit);
/*getchar();
mainexit=getchar();*/
}while(mainexit== 'Y'|| 'y');

return 0;
}

Answer 1

scanf 获取输入但跳过前导空格字符，如空格、换行符空格等。 所以第一个输入之后的新行存储在缓冲区中，以便下一个 scanf 获取输入 那个。

所以避免这种情况，您可以在 scanf 控制字符串之前使用空格。赞这个scanf(" %c",&exit);