6.

1 #include 
     
       2  3 void echo(); 4  5 int main() 6 { 7     /* 8     echo(); 9     echo();10     echo();11     printf("\n");12     echo();13     echo();14     printf("\n");15     echo();16     */17     int i, flag, num = 3;18     19     for (i = num; i > 0; i--)20     {21         flag = i;22         while(flag)23         {24             echo();25             flag -= 1;26         }27         printf("\n");28     }29 30     31     getchar();32     return 0;33 }34 35 void echo()36 {37     printf("Smile!");38 }
     

输出:

Smile!Smile!Smile!

Smile!Smile!

Smile!