RandomGenerator问题

Question

所以我创建了一个扩展acm包的RandomGenerator类的新类！我编译时遇到错误： ＆＃34; RandomGeneratorExtended.java：3：错误：期望的类，接口或枚举 private rgen = RandomGenerator.getInstance（）;＆＃34;

出了什么问题？

import acm.util.*;

private RandomGenerator rgen = RandomGenerator.getInstance();

public class RandomGeneratorExtended {
    public int nextSquare(int n){
        double root= Math.sqrt(n);
        int lim = (int)root;
        int square = rgen.nextInt(0,lim);
        return square*square;
    }

    public int nextSquare(int low, int high){
        double rootlow = Math.sqrt(low);
        double roothigh = Math.sqrt(high);
        int lowlim = (int)rootlow;
        int highlim = (int)roothigh;
        int square = rgen.nextInt(lowlim, highlim);
        return square*square;
    }
}

Answer 1

将类中的随机生成器实例定义为实例变量：

public class RandomGeneratorExtended {
    private RandomGenerator rgen = RandomGenerator.getInstance();//private to class instance
....