Scanf 漏线 [英] Scanf missed line

问题描述

我编写了一个测试程序，它应该接收一个 3x3 的字符矩阵并输出输入的矩阵.但是，我必须输入 4 行才能让程序生成相应的矩阵.我查了 scanf 函数的问题，但我尝试过的解决方案似乎都不起作用……你能帮我解决这个问题吗?

I wrote a test program which should take in a 3x3 matrix of characters and output the entered matrix. However, I have to enter 4 lines in order for the program to produce the corresponding matrix. I have looked up problems on the scanf function, but none of the solutions I tried seemed to work...Could you help me out with this?

我的代码:

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

 int main(void) {


     char a[3][3];
     int i,j;

     for(i=0;i<3;++i)
     {
        for(j=0;j<3;++j)
        {
            scanf("%c",&a[i][j]);
        }
        scanf("\n");
     }

     for(i=0;i<3;++i)
     {
        for(j=0;j<3;++j)
        {
            printf("%c",a[i][j]);
        }
        printf("\n");
     }

     system("PAUSE");

     return(0); }

推荐答案

已经尝试过您的并且它有效.虽然，我确实对每个评论做了一些更改:

Have tried your and IT WORKED. Although, I did make a few changes per comments:

#include <stdio.h>  // added, but that shouldn't matter
main()
{
     char a[3][3];
     int i,j;

     for(i=0;i<3;++i)
     {
        for(j=0;j<3;++j)
        {
            scanf("%c",&a[i][j]);
        }
        //scanf("\n"); // not necessary, see below
     }

     for(i=0;i<3;++i)
     {
        for(j=0;j<3;++j)
        {
            printf(" %c",a[i][j]);
        }
        printf("\n");
     }

     return(0);

}

在 Eclipse/Microsoft C Compiler 上编译并运行此代码并输入一系列字符，然后按 Enter.

Compiled and ran this code on Eclipse/Microsoft C Compiler and entered series of characters followed by enter.

abcdefghi
 a b c
 d e f
 g h i

混淆点可能是 scanf 从控制台缓冲区中提取数据.通常，(尽管您可以解决此问题)当您按 Enter 时，该缓冲区会返回到您的程序.此外，%c 的格式说明符也接受空格.因此，我尝试使用以下输入和输出进行第二次运行.

The point of confusion might be that scanf pulls the data from a console buffer. Typically, (although you can work around this) that buffer is returned to your program when you press enter. Also, the format specifier of %c also accepts blanks. Thus, I tried a second run with the following input and output.

a b c d e 
 a   b
   c  
 d   e

您可以分辨出空格和字母已被读取和存储.

You can tell the spaces were read and stored as well as the letters.

希望这会有所帮助.

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