这个代码哪里有问题啊

public class SavingAccount extends Account {
private double interestRate;
public SavingAccount(double init_balance,double interest_rate) {
  super(init_balance);
  interestRate=interest_rate;
}
@Override//withdraw()是一个抽象方法
public boolean withdraw(double amount) {
  if(amount<=balance){balance-=amount;return true;}
  else return false;
}