c - 帮助进行简单的 C 编程练习

Question

我是 C 编程的新手，在编程练习中遇到了一些困难，我相信这对于任何了解 C 的人来说都很简单，不幸的是你必须遵守练习的规则。

这是练习:

Have a program request the user to enter an uppercase letter. Use nested loops to produce a pyramid pattern like this:

    A 

   ABA

  ABCBA

 ABCDCBA

ABCDEDCBA

The pattern should extend to the character entered. For example, the preceding pattern would result from an input value of E. Hint: Use an outer loop to handle the rows. Use three inner loops in a row, one to handle the spaces, one for printing letters in ascending order, and one for printing letters in descending order.

所以我走到这一步:

#include <stdio.h>

int main(void) {

 int rows;
 int spaces;

 char asc;
 char desc;
 char input;

 printf("Please enter an uppercase letter: ");
 scanf("%c", &input);

 for (rows = 'A'; rows <= input; rows++) {
  for (spaces = input; spaces > rows; spaces--) {
   printf(" ");
  }
  for (asc = 'A'; asc <= rows; asc++) {
   printf("%c", asc);
  }
  for (desc = asc - 2; desc >= rows; desc--) {
   printf("%c", desc);
  }
  printf("\n");
 }
 return 0;
}

Answer 1

你非常接近:

for (desc = asc - 2; desc >= 'A'; desc--) {

请注意，在第二个内循环之后，asc 为rows + 1。然后将 desc 初始化为 rows - 1。您应该能够明白为什么 >= rows 是错误的，并且不会导致迭代。

正确的条件是 >= 'A'。