Java For Loop Unreachable Code

Question

I have a for loop in my code that's giving an error on the entire loop itself, saying it's "unreachable code". I'm completely unsure about what's causing this with this loop:

public ArrayList<Double> Update(ArrayList<Double> addInputs) 
{
// stores the resultant outputs from each layer

ArrayList<Double> outputs = null;

int cWeight = 0;

// first check that we have the correct amount of inputs

if (addInputs.size() != numInputs);
{
    // just return an empty vector if incorrect
    return outputs;
}

// For each layer....


for (int i = 0; i < numHiddenLayers + 1; ++i)
{
    if (i > 0)
    {
        addInputs = outputs;
    }

    outputs.clear();

    cWeight = 0;

    // for each neuron sum the (inputs * corresponding weights) .Throw

    // the total at our sigmoid function to get the output.

    for (int j = 0; j < neuronLayers.get(i).numNeurons; ++j)
    {
        double netinput = 0;

        int numberInputs = neuronLayers.get(i).listNeurons.get(j).numInputs;

    // for each weight

    for (int k = 0; k < numberInputs - 1; ++k)
    {
        // sum the weights x inputs

        netinput += neuronLayers.get(i).listNeurons.get(j).weights.get(k) *
                addInputs.get(cWeight++);
    }

    // add in the bias

    netinput += neuronLayers.get(i).listNeurons.get(j).weights.get(numberInputs - 1)
            *  dBias;

    // we can store the outputs from each layer as we generate them.

    // the combined activation is first filtered through the sigmoid

    //function

    outputs.add(sigmoid(netinput,dActivationResponse));
    }
}

It's claiming the entire for loop after

// For each layer....

is unreachable code. Any help would be greatly appreciated.

score 3 · Accepted Answer · answered Nov 16 '17 at 15:52

3

You have a semicolon here, so the method is always returning outputs. Just remove it

if (addInputs.size() != numInputs); // <---- this one
{
    // just return an empty vector if incorrect
    return outputs;
}

answered Nov 16 '17 at 15:52

Héctor

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i'm a complete idiot! I didn't notice it because it flagged up the entire "for" block and i was assuming the error was with that. Fixed that and I had to insert "Return outputs" right at the end as well, so that's two errors fixed. Thanks very much for the help! – Joseph Oliver Nov 16 '17 at 16:00
You aren't, we all can be mistaken. Glad to help you! – Héctor Nov 16 '17 at 16:02

score 1 · Answer 2 · answered Nov 16 '17 at 15:52

1

You have a semicolon at the end of your if:

... != numInputs);

Meaning the return underneath it will always happen, making the code under it unreachable.

Remove the semicolon.

answered Nov 16 '17 at 15:52

Carcigenicate

43,494
9
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score 0 · Answer 3 · answered Nov 16 '17 at 15:54

0

It is saying because if condition terminates because of semicolon

So return will always execute which transfer control to the caller function skipping you rest of the code

answered Nov 16 '17 at 15:54

Digvijaysinh Gohil

1,367
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Java For Loop Unreachable Code

3 Answers3