PTA 7-5 Output triangle character array (15 points)

7-5 Output Triangular Character Array (15 points)
This question requires writing a program to output n rows of triangular character arrays starting with a capital letter A.

Input format:
Input a positive integer n (1≤n<7) in one line.

Output format:
output n rows of triangle character array starting with capital letter A. See the output sample for the format, where there is a space after each letter.

Input sample:

4

Sample output:

A B C D
E F G
H I
J

在这里插入代码片
#include<stdio.h>
#include<math.h>//在此可有可无。
int main()
{
    char c='A';//定义字符，从A开始。
    int n;//输入的行数，每行的字符数
    scanf("%d",&n);
    while(n)//括号内n 表示n！=0.
    {
        int i;
        for(i = 0; i < n; i++)
      {      putchar(c++);//字符变化，eg：A→B
            printf(" ");//每个字符后面都有一个空格。
      }
        n--;
        printf("\n");//输入一行之后，换行。
    }
    return 0;
}