Write a class named gastank containing:
an instance variable named amount of type double, initialized to 0.
a method named addgas that accepts a parameter of type double.
the value of the amount instance variable is increased by the value of the parameter.
a method named usegas that accepts a parameter of type double.
the value of the amount instance variable is decreased by the value of the parameter.
a method named getgaslevel that accepts no parameters.
getgaslevel returns the value of the amount instance variable.

The answer to this question can be given as:

Class definition:

public class GasTank   //define class GasTank

{

private double amount = 0;  //define variable.

public void addGas(double x)  //define function addGas.

{

amount=amount+x;   //calculate value.

}

public void useGas(double x)  //define function useGas.

{

amount=amount-x;   //calculate value.

}

public double getGasLevel()  //define function getGasLevel

{

return amount;   //return value.

}

}

Explanation:

The description of the above class definition can be given as:

answer; certification; plz check first, i believe this is correct. good luck;