C语言，海龟作图程序，我测试每次都是直接第一行全为1，不知道哪个地方错了

C语言，海龟作图程序，我测试每次都是直接第一行全为1，不知道哪个地方错了

//作图部分改了一下，自己看吧
                           switch(dir%4)//pos表示方向:0向上；1向右；2向下；3向左。初始化为0
                           {
                                   case 0:
                                           while (r-->0 && x >= 0)
                                           {
                                                   str[x--][y]=tmp;
                                           }
                                           x++;
                                           break;
                                   case 1:
                                           while (r-->0 && y                                           {
                                                   str[x][y++]=tmp;
                                           }
                                           y--;
                                           break;
                                   case 2:
                                           while (r-->0 && x                                           {
                                                   str[x++][y]=tmp;
                                           }
                                           x--;
                                           break;
                                   case 3:
                                           while (r-->0 && y>=0)
                                           {
                                                   str[x][y--]=tmp;
                                           }
                                           y++;
                                           break;
   
                           }
追问：　　谢谢前辈，我测试了，能解决一排全是1这个问题。
　　不过还没有全部解决问题