What does unreachable statement mean?

Question

I'm trying to write an Exception to prevent a denominator in my program from being 0.
public String toString()
        return num + "/" + denom;   
        if(denom == 0)
            IllegalArgumentException exception = new IllegalArgumentException("fractions must not have denominators of zero");
            throw exception;
    }But all I get is unreachable statement.

Answer 1

Knotty_Boy wrote:
Ah that makes sense then, I'm a bit confused where I'm meant to put the code then, I'm carrying out 4 different operations on the fractions (add, subtract, multiply, divide) I need to ensure that the denom isn't a 0, so would I be best creating a method that tests for a zero Yes. Follow the DRY principle: Don't Repeat Yourself. If you find yourself writing the same code in several places, put that code into a method.
and then calling that at the end of each of the 4 operations and then throwing an exception if the answer is incorrect?No. Why would you do it at the end? You have to do it at the beginning. When you return, the method ends, and nothing after the return statement is executed. That's why you get that exception, as people have been explaining.
When you go to the cash machine, and ask for $50,000, does it first spit out the money, and then tell you "Insufficient funds"? If so, please tell me where you bank!