在 C99 中构建字母金字塔

Question

#include <stdio.h>
#define FINISH 'Z'
int main(void){
    int spacenm, currentspacenm, i;
    char ini, inirecord;
    int rownm, currentrownm;
    printf("PLease enter a random uppercase letter: ");
    scanf("%c", &inirecord);
    spacenm = rownm = FINISH - inirecord;
    for (i = 0; i<= spacenm; i++)
        printf(" ");
    printf("%c\n", inirecord);
    i = 0;
    for (currentrownm = 1; currentrownm <= rownm; currentrownm ++){
        for (currentspacenm = 1; currentspacenm <= spacenm; currentspacenm++)
            printf(" ");
        spacenm--;
        for (ini = inirecord; ini<=inirecord+i; ini++)
            printf("%c", ini);
        i++;
        for (; ini>=inirecord; ini--)
            printf("%c", ini);
        printf("\n");
    }
    return 0;
}

我想知道是否有更好的方法需要更少的变量或使用更少的冗余代码结构来提高效率。

Answer 1

我们初学者应该互相帮助。:)

您的程序中没有检查用户输入是否有效。

另外，如果我没记错的话，并非所有编码表，例如 EBCDIC 表都包含顺序大写字母。

不需要像你这样写单独的sn-p代码来输出金字塔的第一行

for (i = 0; i<= spacenm; i++)
    printf(" ");
printf("%c\n", inirecord);

使用格式化可以消除循环次数。

考虑到一般情况下，而不是这种格式规范

scanf("%c", &inirecord);
      ^^^^ 

你应该使用以下

scanf(" %c", &inirecord);
      ^^^^^ 

否则也会读取控制字符。

这是我的三分钱。:)

#include <stdio.h>
#include <ctype.h>
#include <string.h>

int main(void) 
{
    const char *letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    const size_t N = strlen( letters );

    while ( 1 )
    {
        char alpha[3];
        _Bool exit_status;
        const char *p;

        do
        {
            printf( "PLease enter a random uppercase letter (Enter - exit ): " );
            exit_status = fgets( alpha, sizeof( alpha ), stdin ) == NULL || alpha[0] == '\n'; 

            if ( !exit_status ) 
            {
                p = NULL;
                if ( alpha[1] == '\n' )
                {
                    alpha[0] = toupper( ( unsigned char )alpha[0] );
                    p = strchr( letters, alpha[0] );
                }
            }
        } while ( !exit_status && !p );     

        if ( exit_status ) break;

        int n = &letters[N] - p;

        putchar( '\n' );
        for ( int i = 0; i < n; i++ )
        {
            printf( "%*c", n - i, alpha[0] );
            int j = 0;
            while ( j != i ) putchar( p[++j] );
            while ( j != 0 ) putchar( p[--j] );
            putchar( '\n' );
        }
        putchar( '\n' );
    }

    return 0;
}

程序输出可能看起来像

PLease enter a random uppercase letter (Enter - exit ): Z

Z

PLease enter a random uppercase letter (Enter - exit ): Y

 Y
YZY

PLease enter a random uppercase letter (Enter - exit ): X

  X
 XYX
XYZYX

PLease enter a random uppercase letter (Enter - exit ): A

                         A
                        ABA
                       ABCBA
                      ABCDCBA
                     ABCDEDCBA
                    ABCDEFEDCBA
                   ABCDEFGFEDCBA
                  ABCDEFGHGFEDCBA
                 ABCDEFGHIHGFEDCBA
                ABCDEFGHIJIHGFEDCBA
               ABCDEFGHIJKJIHGFEDCBA
              ABCDEFGHIJKLKJIHGFEDCBA
             ABCDEFGHIJKLMLKJIHGFEDCBA
            ABCDEFGHIJKLMNMLKJIHGFEDCBA
           ABCDEFGHIJKLMNONMLKJIHGFEDCBA
          ABCDEFGHIJKLMNOPONMLKJIHGFEDCBA
         ABCDEFGHIJKLMNOPQPONMLKJIHGFEDCBA
        ABCDEFGHIJKLMNOPQRQPONMLKJIHGFEDCBA
       ABCDEFGHIJKLMNOPQRSRQPONMLKJIHGFEDCBA
      ABCDEFGHIJKLMNOPQRSTSRQPONMLKJIHGFEDCBA
     ABCDEFGHIJKLMNOPQRSTUTSRQPONMLKJIHGFEDCBA
    ABCDEFGHIJKLMNOPQRSTUVUTSRQPONMLKJIHGFEDCBA
   ABCDEFGHIJKLMNOPQRSTUVWVUTSRQPONMLKJIHGFEDCBA
  ABCDEFGHIJKLMNOPQRSTUVWXWVUTSRQPONMLKJIHGFEDCBA
 ABCDEFGHIJKLMNOPQRSTUVWXYXWVUTSRQPONMLKJIHGFEDCBA
ABCDEFGHIJKLMNOPQRSTUVWXYZYXWVUTSRQPONMLKJIHGFEDCBA

PLease enter a random uppercase letter (Enter - exit ):