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Compiler says: "missing return statement"...even though I have a return statement!

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Join Date: Apr 2008

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CheeseDonkey CheeseDonkey is offline

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Compiler says: "this method must return a result of type int". That's what I'm doing!

Apr 20th, 2008

This is making me angry. I keep getting a "this method must return a result of type int" error message, but obviously I have a return statement. This is a program that is supposed to perform a sequential search for a string index.

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
public static int nameSearch(String[] inOrder, String searchedFor)
{
	for (int i = 0; i < inOrder.length; i++)
	{
		if (searchedFor == inOrder[i])
		{	
			return i;
		}
		else if (i > inOrder.length)
		{
			return -1;
		}
	}
}
public static int nameSearch(String[] inOrder, String searchedFor)
{
	for (int i = 0; i < inOrder.length; i++)
	{
		if (searchedFor == inOrder[i])
		{	
			return i;
		}
		else if (i > inOrder.length)
		{
			return -1;
		}
	}
}

Does anybody know what is wrong?

Last edited by CheeseDonkey; Apr 20th, 2008 at 9:29 pm.

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Join Date: Apr 2008

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ikugan26

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Re: Compiler says: "missing return statement"...even though I have a return statement

Apr 20th, 2008

Dont use return statement inside if statements, instead use it at the end of your method name search
like this:

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
public static int nameSearch(String[] inOrder, String searchedFor){
       int returnVal = null;
       for (int i = 0; i < inOrder.length; i++){
             if (searchedFor == inOrder[i]){
                     returnVal = i;
             }
              else if (i > inOrder.length){
                    returnVal = -1;
             }
       }
       return returnVal; //return here...
}
public static int nameSearch(String[] inOrder, String searchedFor){
       int returnVal = null;
       for (int i = 0; i < inOrder.length; i++){
             if (searchedFor == inOrder[i]){
                     returnVal = i;
             }
              else if (i > inOrder.length){
                    returnVal = -1;
             }
       }
       return returnVal; //return here...
}

hope this helps ..

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masijade

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Re: Compiler says: "missing return statement"...even though I have a return statement!

Apr 21st, 2008

Of course, that second part of the if statement is completely false anyway. That is what the for loop is for.

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
public static int nameSearch(String[] inOrder, String searchedFor){
    int returnVal = -1;
    if (searchedFor == null) {
        // if searchedFor is null the if in the for loop will have problems.
        return returnVal;
    }
    for (int i = 0; i < inOrder.length; i++) {
        if (searchedFor.equals(inOrder[i])) {
            returnVal = i;
        }
    }
    return returnVal;
}
public static int nameSearch(String[] inOrder, String searchedFor){
    int returnVal = -1;
    if (searchedFor == null) {
        // if searchedFor is null the if in the for loop will have problems.
        return returnVal;
    }
    for (int i = 0; i < inOrder.length; i++) {
        if (searchedFor.equals(inOrder[i])) {
            returnVal = i;
        }
    }
    return returnVal;
}

P.S. You can't set an int to null anyway. ;-)

And, don't use == to compare Strings. ;-)

Last edited by masijade; Apr 21st, 2008 at 1:02 am.

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Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.
--Brian Kernighan

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Join Date: Apr 2008

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ikugan26

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Re: Compiler says: "missing return statement"...even though I have a return statement!

Apr 21st, 2008

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P.S. You can't set an int to null anyway. ;-)

oops! sorry.. and thanks..

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Ezzaral

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Re: Compiler says: "missing return statement"...even though I have a return statement!

Apr 21st, 2008

It's perfectly fine to have return statements within if() blocks. The issue here is that there is not a guaranteed return path from the method. For instance, in the original code if inOrder.length is 0, there is no return. The compiler requires a valid return path regardless of any conditional statements and that is why you could not compile it.

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masijade

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Re: Compiler says: "missing return statement"...even though I have a return statement!

Apr 21st, 2008

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Originally Posted by Ezzaral

It's perfectly fine to have return statements within if() blocks. The issue here is that there is not a guaranteed return path from the method. For instance, in the original code if inOrder.length is 0, there is no return. The compiler requires a valid return path regardless of any conditional statements and that is why you could not compile it.

Yes, you can return from an if. However, if the only return statement you have is contained within an if statement, and the compiler cannot confirm that every possible avenue has been covered, you will still get a "missing return statement".

i.e.

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
public String aMethod() {
  int x = 0;
  //do something with x
  if (x == 0) {
    return "Hello";
  }
}
public String aMethod() {
  int x = 0;
  //do something with x
  if (x == 0) {
    return "Hello";
  }
}

will cause the compiler to throw that error, as the compiler cannot confirm that something will be returned. If you are going to return from an if statement, then return from every block in the if statement and include an else that also has a return statement or have a return statement at the end of the method.

i.e.

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
public String aMethod() {
  int x = 0;
  //do something with x
  if (x == 0) {
    return "Hello";
  } else if (x == 1) {
    return "GoodBye";
  } else {
    return "Bogus";
  }
}
// or
public String aMethod() {
  int x = 0;
  //do something with x
  if (x == 0) {
    return "Hello";
  }
  return "Bogus";
}
// or
public String aMethod() {
  int x = 0;
  //do something with x
  if (x <= 0) {
    return "Hello";
  } else if (x > 0) {  // the same as a simple else, in this case
    return "GoodBye";
  }
}
public String aMethod() {
  int x = 0;
  //do something with x
  if (x == 0) {
    return "Hello";
  } else if (x == 1) {
    return "GoodBye";
  } else {
    return "Bogus";
  }
}
// or
public String aMethod() {
  int x = 0;
  //do something with x
  if (x == 0) {
    return "Hello";
  }
  return "Bogus";
}
// or
public String aMethod() {
  int x = 0;
  //do something with x
  if (x <= 0) {
    return "Hello";
  } else if (x > 0) {  // the same as a simple else, in this case
    return "GoodBye";
  }
}