打印一个空心菱形

[code=Java]importjava.io.InputStreamReader;


publicclassWork...{
publicstaticvoidmain(String[]args)throwsIOException...{
intlen;//菱长
Stringoutstr=newString();//输出
inti,j,x,y;
BufferedReaderbr=newBufferedReader(newInputStreamReader(System.in));
System.out.println("请输入一个菱长:");
Stringstr=br.readLine();
len=Integer.parseInt(str);
for(i=0;i<=len*2;i++)...{
for(j=0;j<=len*2;j++)...{
x=len-i;
x=x<0?-1*x:x;
y=len+(len-x);
outstr+=(j==x||j==y?"*":"　");
}
outstr+=" ";
}
System.out.println(outstr);
}
}
[/code]