Noob question about using ints in booleans

[elfdreaming]

Okay. I know this is pretty basic stuff. Sorry. This is a trouble I have that I don't know how to deal with. I create a boolean if statement, and at some times it won't let my use int's. Of course I am using ints, but I get an error message "this method must return a type of int" because I created an if statement with booleans... but the return is a number, not a true/false. I just don't see what I'm doing wrong. Sample code:

/* calculates the total amount of time required to cook */
private int totalCookTime(int cookingLength, int foodAmount, int stoves, int cookingLengthMinutes) {
if (cookingLength > 0 && cookingLengthMinutes <= 0) {
return ((cookingLength*foodAmount)*MINUTES_IN_HOUR)/stoves;
} else if (cookingLength > 0 && cookingLengthMinutes > 0){
return (((cookingLength*foodAmount)*MINUTES_IN_HOUR)+cook ingLengthMinutes)/stoves;
} else if (cookingLength <= 0 && cookingLengthMinutes > 0) {
return (cookingLengthMinutes*foodAmount)/stoves;
}
}

of course in the body I have initiated all the parametres etc.

So sorry that this question is so dumb.

Oh, and I use Eclipse, if that makes a difference.

Thanks for your time.

Jo

[Eranga]

Sorry, your method does not have a return in full path.

[sunde887]

Those if statements look fine, are you getting errors? If so, what are they?(don't paraphrase, copy and post the exact error)

Also, use code tags
[c ode]
your code
[/code]

Also, if none of the conditions are met it wont return anything.

[JosAH]

Suppose all of your if-tests fail; the compiler doesn't evaluate your code so that could happen. Your method doesn't return anything so your compiler starts to whine about it; the remedy is simple: stick a "return 0;" at the very end of that method even if it is never executed, the compiler can't tell.

kind regards,

Jos

[masijade]

Your problem is that all of your "returns" are inside of if blocks. The compiler does not even attempt to evaluate those conditions and so it envisions a possibility that none of those if blocks will evaluate as true and, therefore, your method could wind up not returning anything. Either add an else block that returns a default value or add a return at the end of the method that returns a default value, or better yet, rewrite the method in the following manner

public int someMethod(int arg) {
    int retVal = someDefaultValue;
    if (arg > someValue) {
        retVal = someArgExpression;
    } else if (arg < someOtherVale) {
        retVal = someOtherArgExpression;
    }
    return retVal;
}

Edit Man, am I SLOW!

[elfdreaming]

Oh! Thank you very much. When I added the final else statement (which is something that should never happen in the program) it all worked fine. So the error "this method must return a type of int" put me off because I was trying to work out why it wasn't an int!

Thankyou very much. :)

[ozzyman]

This code is pretty messy...

private int totalCookTime(int cookingLength, int foodAmount, int stoves, int cookingLengthMinutes) {
  if (cookingLength > 0 && cookingLengthMinutes <= 0) {
    return ((cookingLength*foodAmount)*MINUTES_IN_HOUR)/stoves;
  } else if (cookingLength > 0 && cookingLengthMinutes > 0){
    return (((cookingLength*foodAmount)*MINUTES_IN_HOUR)+cook ingLengthMinutes)/stoves; 
  } else if (cookingLength <= 0 && cookingLengthMinutes > 0) {
    return (cookingLengthMinutes*foodAmount)/stoves;
  }
}

Firstly, your calculation is the same for the first 2 branches and it only changes in the final branch because if cookinglength <= 0 it renders the major part of your calculation as 0.

What you have written has the same effect as:

int cookingTime = 0;

if (cookingLength <= 0 && cookingLengthMinutes > 0) {
  cookingTime = (cookingLengthMinutes*foodAmount)/stoves;
} else {
  cookingTime = (cookingLength*MINUTES_IN_HOUR*foodAmount + cookingLengthMinutes)/stoves;
}

return cookingTime;

And even then, it appears to me that your variable cookingLengthMinutes indicates the same value as cookingLength*MINUTES_IN_HOUR ? That is, if cookingLength holds the cooking time in Hours and MINUTES_IN_HOUR = 60. In which case, you don't need any conditional statement because the calculation is the same for all values.

EDIT: Looking at your code again, it seems like you are storing the cooking time in two variables: one for hours and another for minutes e.g.
Total cooking time could be 1hr + 30minutes. But it should be all stored in minutes to simplify calculations and can still be output as hours & minutes.
And if that is the case, then:

  cookingTime = (cookingLength*MINUTES_IN_HOUR*foodAmount + cookingLengthMinutes)/stoves;

Should be

  cookingTime = (cookingLength*MINUTES_IN_HOUR*foodAmount + cookingLengthMinutes*foodamount)/stoves;

Infact, then your whole method should look like this:

private int totalCookTime(int cookingLength, int foodAmount, int stoves, int cookingLengthMinutes) {
  int cookingTime = 0;
  cookingTime = (cookingLength*MINUTES_IN_HOUR*foodAmount + cookingLengthMinutes*foodamount)/stoves;
  return cookingTime;
}

i.e. the total minutes for cooking is cooking hours*minutes in hour + cooking minutes
and the total cooking time is (the total minutes*foodamount) divided by number of stoves