/** add(Money value) binary operator returns sum of object plus value */
public Money add(Money value) {
Money result = new Money();
result.cents = cents + value.cents;
result.dollars = dollars + value.dollars;
// Only need to check if cents is greater than 100 since the
// largest value that can result from an addition is 198
if (result.cents >= 100) {
++result.dollars;
result.cents -= 100;
}
return result;
}
/**
* subtract(Money value) binary operator returns the difference between object and value returns
* an error if value is larger than the object calling the method
*/
public Money subtract(Money value) {
Money result = new Money();
// Find the total cents values for the subtrahend (value) and the minuend (this), and compare
// them to make sure
// that the subtrahend is smaller than the minuend.
long myCentsAmount = (this.dollars * 100) + this.cents;
long valueCentsAmount = (value.dollars * 100) + value.cents;
long differenceBetween = myCentsAmount - valueCentsAmount;
if (differenceBetween < 0) { // Subtraction will result in a negative money value
System.out.println(
"! ERROR: Subtraction can't result in a negative Money value! "
+ "Setting dollars and cents to default values of 0.");
} else { // Proper values for subtraction
result.dollars = differenceBetween / 100;
result.cents = differenceBetween % 100;
}
return result;
}
public void closeAccount() {
balance.dollars = 0;
balance.cents = 0;
}