关于c语言中getchar()的问题

 #include<stdio.h>
int main(void)
{
    int guess = 1;

    printf("Pick an integer from 1 to 100. I will try to guess");
    printf("it.\nRespond with a y if my guess is right and with");
    printf("\nan n if it is wrong.\n");
    printf("Uh...is your number %d?\n",guess);
    while (getchar() != 'y')
    {
        if (getchar() =='n')
        printf("Well,then,is it %d?\n", ++guess);
        else
        printf("Sorry,you say what?\n");
        while (getchar() !='\n')
            continue;
    }
    printf("I knew I could do it!\n");
    return  0;
}

 #include<stdio.h>
int main(void)
{
    int guess = 1;
    char response;

    printf("Pick an integer from 1 to 100. I will try to guess");
    printf("it.\nRespond with a y if my guess is right and with");
    printf("\nan n if it is wrong.\n");
    printf("Uh...is your number %d?\n",guess);
    while ((response = getchar()) != 'y')
    {
        if (response =='n')
        printf("Well,then,is it %d?\n", ++guess);
        else
        printf("Sorry,you say what?\n");
        while (getchar() !='\n')
            continue;
    }
    printf("I knew I could do it!\n");
    return  0;
}

为什么这两个程序的运行结果不一样呢？？
为什么需要把getchar()的值赋给response?

许多初学者都习惯用 char 型变量接收 getchar、getc，fgetc 等函数的返回值，其实这么做是不对的，并且隐含着足以致命的错误。getchar 等函数的返回值类型都是int 型
下面是getchar()的定义：
[html] view plaincopyprint?
 
1 int  
2 getchar ()  
3 {  
4   int result;  
5 ......
答案就在这里：C语言中getchar中的问题
----------------------Hi，地球人，我是问答机器人小S，上面的内容就是我狂拽酷炫叼炸天的答案，除了赞同，你还有别的选择吗？

因为每次getchar()都是一个输入数据的动作啊！
把它赋值给response，就能暂存上一个动作的结果了~
第一个程序会造成严重的混乱。