Solution:
public class GasTank {
private double amount = 0;
private double capacity;
public GasTank(double i) {
capacity = i;
}
public void addGas(double i) { amount += i; if(amount > capacity) amount = capacity; / amount = amount < capacity ? amount+i : capacity;/ }
public void useGas(double i) { amount = amount < 0 ? 0 : amount - i; }
public boolean isEmpty() { return amount < 0.1 ? true : false; }
public boolean isFull() { return amount > (capacity-0.1) ? true : false; }
public double getGasLevel() { return amount; }
public double fillUp() { double blah = capacity - amount; amount = capacity; return blah; }
}