scanf函数未扫描％C字符，但跳过的说法，这是为什么？ [英] Scanf is not scanning %c character but skips the statement, why is that?

问题描述

我使用开关case语句写了一个程序，要求输入一个字符，但它不要求在控制台窗口中的字符，但完全跳过它。

I wrote a program using switch case statement and asked for a char for input but it does not ask for the char in the console window but skips it completely

int main() 
{
    float a, b, ans;
    char opr;

    printf("\nGIVE THE VALUES OF THE TWO NUMBERS\n");
    scanf(" %f %f",&a,&b);


    printf("\nGIVE THE REQUIRED OPERATOR\n");   

    //no display(echo) on the screen
    //opr = getch();
    //displays on the screen
    //opr = getche();

    scanf("%c",&opr);

    switch(opr)
    {
        case '+' :
            ans = a+b;
            printf("%f", ans);
            break;          
        case '-' :
            ans = a-b;
            printf("%f", ans);
            break;          
        case '*' :
            ans = a*b;
            printf("%f", ans);
            break;          
        case '/' :
            ans = a/b;
            printf("%f", ans);
            break;
        case '%' :
            ans = (int)a % (int)b;
            printf("%f", ans);
            break;
        default :
            printf("\nGIVE A VALID OPRATOR\n");

    }

    system("pause");        
    return 0;

但是当我在第二把空间之前％C scanf函数它的工作原理有人讲了一些关于空白，我发现混乱

but when i put a space before %c in the second scanf it works someone was telling something about a whitespace which i found confusing

他说，第二个 scanf函数正在的\\ N值作为一个字符，如果我把一个空间前％C 第二 scanf函数不是一个字符，不将其乘坐空间作为字符？

He said the second scanf is taking the value of \n as a character and if i put a space before %c in the second scanf isn't that a character and doesn't it take the space as the character?

不过，这个计划不会采取 \\ n 作为字符

But in this program it does not take the \n as the character

int main() 
{
    char a;
    printf("\ngive a char\n");
    scanf("%c",&a);
    printf("%c",a);

    return 0;
}  

这是真的混淆可以在任何帮助我，我想了解什么是错的。

This is really confusing can any on help me i want to learn what is wrong.

推荐答案

每次使用scanf的这种格式时间：

Every time you use scanf with this format :

scanf("%c",&a); 

它离开，这将在下一迭代中消耗的换行符。
你提到的日最后一个节目只有一个scanf函数。尝试使用其他scanf函数。你会得到同样的问题。

it leaves a newline which will be consumed in the next iteration. Th last program that you mentioned have only one "scanf". try to use another scanf. you will get the same problem.

所以要避免空格你必须写：

so to avoid white spaces you have to write :

 scanf(" %c",&opr); 

格式字符串前的空格告诉scanf函数忽略空格。或它更好地使用

the space before the format string tells scanf to ignore white spaces. Or its better to use

getchar();

这会消耗你所有的换行

It will consume all your newline

这篇关于scanf函数未扫描％C字符，但跳过的说法，这是为什么？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！