字符处理和字符迭代

Question

来源:

#include <stdio.h>

void main()

{

int i, j, tree_Size, spaces, total_Spaces, x;
char tree_Characters;

printf("Enter characters to use --> ");
 scanf("%c", &tree_Characters);
printf("Enter size of tree --> ");
 scanf("%d", &tree_Size);

   //For handling top part of tree
   for (i = 0; i <= tree_Size; i++) {
      printf("\n");
      total_Spaces = tree_Size - i;

        //Determine spaces before each number for pyramid
      for (spaces = 1; spaces <= total_Spaces; spaces++) 
         printf(" ");

      //Make first line always one number
      for (j = -1; j < i; j++)
         if (j <= -1)
            printf("%c", tree_Characters);
         else if (j > -1)
            printf("%c%c", tree_Characters, tree_Characters);
   } 

   //For handling stem and base of tree
   for (i = 0; i <= tree_Size; i++) {

      //if handling stem
      if (i < tree_Size) {
         printf("\n");  
         for (spaces = 1; spaces <= tree_Size; spaces++)
            printf(" ");
         printf("%c", tree_Characters);
      }

      //else if handling base

      else if (i == tree_Size) {
         printf("\n");

         for (x = 0; x <= tree_Size * 2; x++) {
            printf("%c", tree_Characters);
         }
      }
   }

printf("\n");

}

Here is the output it produces so far
Here is a thread I made on reddit for better understanding (comments)

任务的目标是让它看起来像这样:

*** Print a Tree ***

Enter characters to use ---   *|=+
Enter size of tree      ---   4

    *
   ***
  *****
 *******
*********
    |
    |
    |
    |
====+====

我不明白的是如何处理字符。老师提到将字符放入某个缓冲区然后清除它等，我不知道。谁能帮忙？我必须使用 scanf，无法将任何内容转换为字符串或使用任何高级内容。

Answer 1

您需要使 tree_Characters 成为一个数组(char tree_Characters[5] 用于五元素数组，它将包含四个树字符和一个 nul 终止符)，并且更改第一个 scanf。

scanf("%4s%*[^\n]",tree_Characters);
//      vv\_____/  ^-- array will decay to char*
//      ||   \-- discard the rest of the line
//      ||         ("*" indicates discard, "[^\n]" matches everything but '\n')
//      |\-- string (non-whitespace characters only)
//      \-- at most four characters scanned

参见 http://linux.die.net/man/3/scanf获取更多信息。

编辑:您当然必须更改程序的其余部分，以便为每个树元素选择适当的字符。 (参见 @eznme's answer。)

编辑:无数组版本:

char tree_leaf,tree_stem,tree_ground,tree_root;
scanf("%c%c%c%c%*[^\n]",&tree_leaf,&tree_stem,&tree_ground,&tree_root);

这会对太短的输入行产生不良 react 。