c - 用 C99 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，需要更少的变量或者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。:)

您的程序中不会检查用户输入是否有效。

此外，如果我没有记错的话，并非所有编码表(例如 EBCDIC 表)都包含连续的大写字母。

无需像您所做的那样编写单独的代码片段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数量。

考虑到一般情况而不是这种格式规范

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

您应该使用以下内容

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

否则控制字符也会被读取。

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;
}

程序输出可能如下所示

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 ):