JAVA蓝桥杯黄金分割数，涉及到bigdecimal

import java.math.BigDecimal;

public class test {

    public static void main(String[] args) {
        BigDecimal one, ans;

        ans = one = BigDecimal.ONE;

        for (int i = 0; i < 1000; i++) {
            ans = one.add(ans);

            ans = one.divide(ans, 200, BigDecimal.ROUND_HALF_UP);
            System.out.println(ans);

        }

        System.out.println(ans.setScale(100, BigDecimal.ROUND_HALF_UP));
    }

}

bigdecimal.round_half_up