怎么写，我是刚学不会求帮助

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        System.out.println("输入性别：");
        String sex=in.next();
        System.out.println("输入百米赛成绩：");
        float m=in.nextFloat();
        if (m<10){
            if (sex.equals("男")){
                System.out.println("进入男子组");
            }else{
                System.out.println("进入女子组");
            }
        }else{
            System.out.println("很遗憾，未能进入决赛！");
        }
    }
}

 public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入是否是会员：是（y）/否（其他字符）");
        String str = scanner.next();
        if ("y".equals(str)) {
            System.out.println("请输入购物金额：");
            BigDecimal bigDecimal = scanner.nextBigDecimal();
            if (bigDecimal.compareTo(new BigDecimal("200")) > 1) {
                bigDecimal = bigDecimal.multiply(new BigDecimal("0.75"));
            }else {
                bigDecimal = bigDecimal.multiply(new BigDecimal("0.8"));
            }
            System.out.println("实际支付：" + bigDecimal);
        }else {
            System.out.println("请输入购物金额：");
            BigDecimal bigDecimal = scanner.nextBigDecimal();
            if (bigDecimal.compareTo(new BigDecimal("100")) > 1) {
                bigDecimal = bigDecimal.multiply(new BigDecimal("0.9"));
            }
            System.out.println("实际支付：" + bigDecimal);
        }
    }