Ok, in my last post I had mensioned that I would add more methods. I
added a
subtract method that would subtract two fractions. I get an error when
running the program with J2SDK. When I run the program with Eclipse, it
runs
fine, except for the error that it mensions after it has finished
running.
Here is my Fraction class.
public class Fraction
{
int numerator; // Holds numerator
int denominator; // Holds denominator
// Constructor passes int values from num and denum to numerator, and
denominator.
public Fraction(int num, int denom)
{
numerator = num;
denominator = denom;
}
// Default constructor sets data fields to 0
public Fraction()
{
numerator = 0;
denominator = 0;
}
// Methods return values of numerator and denominator
public int getNumerator() { return numerator; }
public int getDenominator() { return denominator; }
// Method returns printed formatted string
public String toString()
{
return numerator + "/" + denominator;
}
// Method adds two fractions together
public Fraction add(Fraction frac1)
{
Fraction fraction_1 = new Fraction();
Fraction fraction_2 = new Fraction();
Fraction result = new Fraction();
Fraction printResult = new Fraction();
fraction_1.denominator = denominator * frac1.denominator;
fraction_1.numerator = numerator * frac1.denominator;
fraction_2.denominator = frac1.denominator * denominator;
fraction_2.numerator = frac1.numerator * denominator;
result.numerator = fraction_1.numerator + fraction_2.numerator;
result.denominator = denominator * frac1.denominator;
printResult = new Fraction(result.numerator, result.denominator);
return printResult;
}
// Method subtracts two fractions
public Fraction subtract(Fraction frac1)
{
Fraction fraction_1 = new Fraction();
Fraction fraction_2 = new Fraction();
Fraction result = new Fraction();
Fraction printResult = new Fraction();
fraction_1.denominator = denominator * frac1.denominator;
fraction_1.numerator = numerator * frac1.denominator;
fraction_2.denominator = frac1.denominator * denominator;
fraction_2.numerator = frac1.numerator * denominator;
result.numerator = fraction_1.numerator - fraction_2.numerator;
result.denominator = denominator * frac1.denominator;
// If both numerator and denominator are negative
if (result.numerator < 0 && result.denominator < 0)
{
printResult = new Fraction(Math.abs(result.numerator),
Math.abs(result.denominator));
return printResult;
}
if (result.numerator > 0 && result.denominator < 0)
{
printResult = new Fraction(result.numerator*-1,
Math.abs(result.denominator));
return printResult;
}
}
} // End of class
Here is my source code for the driver class.
import java.util.Scanner; // Import Scanner class
// Class FractionDriver inputs two fractions and adds and subtracts them
public class FractionDriver
{
public static void main(String[] args)
{
// Declare local data fields
int numerator; // Holds numerator
int denominator; // Holds denominator
Scanner inData = new Scanner(System.in); // Scanner object
Fraction frac1 = new Fraction();
Fraction frac2 = new Fraction();
Fraction answer = new Fraction();
// Ask user for numerators and denominators.
System.out.println("Enter numerator for fraction 1:");
numerator = inData.nextInt();
System.out.println("Enter denominator for fraction 1:");
denominator = inData.nextInt();
frac1 = new Fraction(numerator, denominator);
System.out.println("Fraction 1 is " + frac1 + ".");
System.out.println("Enter numerator for fraction 2:");
numerator = inData.nextInt();
System.out.println("Enter denominator for fraction 2:");
denominator = inData.nextInt();
frac2 = new Fraction(numerator, denominator);
System.out.println("Fraction 2 is " + frac2 + ".");
answer = frac1.add(frac2);
System.out.println(frac1 + " + " + frac2 + " = " +
answer);
answer = frac2.subtract(frac1);
System.out.println(frac2 + " - " + frac1 + " = " +
answer);
}
}
When I run the program with Eclipse, this is what I get.
Enter numerator for fraction 1:
2
Enter denominator for fraction 1:
5
Fraction 1 is 2/5.
Enter numerator for fraction 2:
3
Enter denominator for fraction 2:
7
Fraction 2 is 3/7.
2/5 + 3/7 = 29/35
Exception in thread "main" java.lang.Error: Unresolved compilation
problem:
This method must return a result of type Fraction
at Fraction.subtract(Fraction.java:49)
at FractionDriver.main(FractionDriver.java:33)
When I run the program with J2SDK, I get the following.
C:\Users\user\Desktop\COMP268\Practice\Fractions\src>javac *.java
Fraction.java:74: missing return statement
}
^
1 error
C:\Users\user\Desktop\COMP268\Practice\Fractions\src>
What am I doing wrong?
Gilbert Neiva
