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Returning values from arrays  RSS feed

 
Ciara O'Hara
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Hello,

I have created a class and a matrix of doubles (or at least, I think I have, that's partly what I want to verify).

I need to return the values of the array, but I don't know how, and I can't seem to google find the answer.

Here is my class:



I am getting the error: "This method must return a result of type double", though to me it looks like I am returning double (A), so I'm confused.

Any help appreciated.
 
Joanne Neal
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Ciara O'Hara wrote:I am getting the error: "This method must return a result of type double", though to me it looks like I am returning double (A), so I'm confused.

The compiler isn't clever enough to know that you will always enter the for loop, therefore it is complaining that, if the for loop is not executed, there is no return statement.

Having said that, why have you got a for loop anyway ? It returns every time during the first iteration, so your code is basically the equivalent of
 
Ciara O'Hara
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Thanks Joanne Neal,

I can ignore the for loop. I'm going to simplify it a bit more:



Now I'm getting: "Type mismatch: cannot convert from double to double[][]". I have also tried just 'double', no luck.

I want to return a value from the matrix. Thanks again.
 
Joanne Neal
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Ciara O'Hara wrote:I want to return a value from the matrix. Thanks again.

In that case you need to change the return type of your method (it is currently declared to return an array of double arrays) and also the type of the A variable.

And when you've fixed that you need to know that array indexes start from 0 and go to n - 1, where n is the length of the array.
 
Winston Gutkowski
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Ciara O'Hara wrote:I want to return a value from the matrix.

OK, but that's NOT what you're doing - at least in the last code you posted - because you've declared the methods as:
double[][] eg() { ...

So: What does that return?

PS: I think you could make things a lot easier for yourself (and us) if you gave these methods descriptive names. What are we supposed to think a method called 'eg()' does?

Winston
 
Campbell Ritchie
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And welcome to the Ranch
 
Ciara O'Hara
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Winston Gutkowski wrote:
OK, but that's NOT what you're doing - at least in the last code you posted - because you've declared the methods as:
double[][] eg() { ...



I know that's not what I am doing, that's what I can't figure out how to do! I was just posting a simplified example to try to illustrate my issue (hence the 'e.g.').

Back to the trial and error ;-).

Thanks

Ciara
 
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