Require some help with Java..

Question

Use of if to simulate modulus operator

Rewrite this increment() method from the NumberDisplay() class without using the % modulus operator.

/** Increment the display value by one *  rolling over to zero if the limit is reached  */
public void increment() 
{
   if(value > limit);
   else
   value = (value + 1);
   value = 0;
}

well, i tested this out, i put value = (value + 1); it complied sucessfully, but the error came up as rollover was less then the amount. any help would be great!

Answer 1

I suggest you read how to properly write an if statement.

Answer 2

I guess you want

public void increment() 
{
   if(value >= limit)
     value = 0;
   else
     value = value + 1;
}

but it definitely smells like homework...

Answer 3

I'm not quite sure exactly what your asking or what you mean by "limit" exactly, but I'm guessing (based on how I expect the mod operator to work) that perhaps you're off by one? Perhaps ">=" instead of ">" is what you're looking for?

Answer 4

You're always assigning 0 to value, unconditionally. You've also got an empty "if" statement, which isn't a good sign - and hard to spot as you've just used ";" instead of braces.

Here's your current code rewritten with braces:

public void increment() 
{
   if(value > limit)
   {
   }
   else
   {
       value = (value + 1);
   }
   value = 0;
}

Now, rather than show you the code itself, I'll give you two hints:

• How would value ever be strictly greater than the limit?
• Why would you not want to change value at all if it's particularly high? What would you want it to become instead?

Answer 5

Hint: watch out for semicolons in strange places.

Hint 2: try using { and } with your if and else blocks, this will help you see the logic of the code.

Answer 6

Without thinking in terms of code syntax and such, try to read what you put as if it were an English sentence. That should give you some idea, e.g.:

If the value is greater than the limit, then ...

Answer 7

public void increment()
{
    value++;
    if(value >= limit)
        value = 0;
}