根据用户输入打印菱形

public class For{

　　

public static void main(String[] args) {
 int rows = 0; //菱形的行数
 Scanner input = new Scanner(System.in);
 System.out.print( "请输入菱形行数：");
 rows = input.nextInt();
 while(rows%2 == 0){
  System.out.print( "请输入奇数：");
rows = input.nextInt();
 }
 int n = (rows+1)/2;
 //打印菱形的上半部分
 for(int i = 1; i <= n; i++){   //外层循环变量i控制行数
  for(int j = 1; j <= n-i; j++){   //内层循环变量j控制该行空格数
   System.out.print( " ");
  }
  for(int k = 1; k <= 2*i-1; k++){   //内层循环变量k控制该行*号数
   System.out.print( "*");
  }
  System.out.print( "\n");
 }
 //打印菱形的下半部分
 for(int i = n-1; i >= 1; i--){
  for(int j = 1; j <= n-i; j++){
   System.out.print( " ");
  }
  for(int k = 1; k <= 2*i-1; k++){
   System.out.print( "*");
  }
  System.out.print( "\n");
 }
}

}