*号图形的输出问题:   

#include<stdio.h>

main()
{
   int a, b, c;
   
   scanf("%d", &a);                        假设a=4, 输出的图形为: ****
                                                                  ****
   for(b=a; b!=0; b--)                                            ****
   {                                                              ****  
       for(c=a; c!=0; c--)
       {  
          printf("*");
       }
      printf("\n");
   }
   getch();
}

这是用for语句输出;
换成while语句输出却得到不同的结果;

#include<stdio.h>

main()
{
   int a, b, c;

   scanf("%d",&a);                         假设a=4;输出的图形为: ****
   c=b=a;                                                        ----
                                                                 ----
   while(b!=0)                                                   ----
   {                                                          (横线表示3个空行)  
      while(c!=0)
      {
          printf("*");
          c--;
      }
      printf("\n");
      b--;
   }
   getch();
}

从输出的结果看,外循环和内循环好象没关系;不知道问题出在哪里,望高手指点. 谢谢.

非常感谢大家的指点!!

分数有限,分配不均,还望各位见谅!!