程序内容如下：
#include<stdio.h>
void main()   
{
  int z=1;
  while(z==1)
  {
    int n,m,l,h,x;
    h=0;
    x=1;
    printf("    谢谢使用画图。\n请输入一个数作为画布边长：");
    while (scanf("%d",&n)!=EOF)
    {
      m=(n+2)/2;
      l=n/2;
      while(h<n/2)
      {
              if(x>=(n*h+m-h)&&x<=(n*h+m+h)) printf("*");else printf(" ");
              if(x%n==0) {printf("\n");h+=1;}
              x+=1;
      }
      while(h<n)
      {
              if(x>=(n*h+l-n+h+1)&&x<=(n*h+l+n-h-1)) printf("*");else printf(" ");
              if(x%n==0) {printf("\n");h+=1;}
              x+=1;
      }
    }
  printf("继续画图输入1，退出输入0.\n");
  scanf("%d\n",&z);
  }  
}