Invalid types 'int[int]' for array subscript error

Question

I'm migrating into C++ from Java world and am trying to port over an example. I'm getting an error in that I'm not accessing my arrays correctly. I tried pointing to them, using -> and * notation but I'm having a hard time getting my head around it. I believe it's the same basic error repeated multiple times. I've highlighted the three areas where the errors begin, excluding the multiples of the same error. Any help would go a long way in my understanding of the topic. Thanks!

//--------------------------------------------------------------
void testApp::setup(){
    colorCount = 20;
    int *hueValues = new int[colorCount];
    int *saturationValues = new int[colorCount];
    int *brightnessValues = new int[colorCount];

ofColor::fromHsb(360, 100, 100, 100);
ofFill();
}

//--------------------------------------------------------------
void testApp::update(){

}

//--------------------------------------------------------------
void testApp::draw(){
    // ------ colors ------
    // create palette
    for (int i=0; i<colorCount; i++) {
        if (i%2 == 0) {
            hueValues[i] = (int) random(0,360);                  // invalid types 'int[int]' fr array subscript
            saturationValues[i] = 100;  
            brightnessValues[i] = (int) random(0,100);
        } 
        else {
            hueValues[i] = 195;
            saturationValues[i] = (int) random(0,100);
            brightnessValues[i] = 100;
        }
    }

    // ------ area tiling ------
    // count tiles
    int counter = 0;
    // row count and row height
    int rowCount = (int)random(5,40);                  // At this point in file
    float rowHeight = (float)ofGetHeight()/(float)rowCount;

    for(int i=0; i<rowCount; i++) {
        // seperate each line in parts  
        // how many fragments
        int partCount = i+1;
        parts = new float[0];                  // Cannot convert "float" to "float" in assignment

        for(int ii=0; ii<partCount; ii++) {
            // sub fragments or not?
            if (random(1.0) < 0.075) {
                // take care of big values      
                int fragments = (int)random(2,20);
                partCount = partCount + fragments; 
                for(int iii=0; iii<fragments; iii++) {
                    parts = append(parts, random(2));
                }              
            }  
            else {
                parts = append(parts, random(2,20));   
            }
        }

        // add all subparts
        float sumPartsTotal = 0;
        for(int ii=0; ii<partCount; ii++) sumPartsTotal += parts[ii];

        // draw rects
        float sumPartsNow = 0;
        for(int ii=0; ii<parts.length; ii++) {
            // get component color values
            int index = counter % colorCount;
            fill(hueValues[index],saturationValues[index],brightnessValues[index]);

            sumPartsNow += parts[ii];
            rect(map(sumPartsNow, 0,sumPartsTotal, 0,width),rowHeight*i, 
                 map(parts[ii], 0,sumPartsTotal, 0,width)*-1,rowHeight);

            counter++;
        }
    }  
}

int *hueValues = new int[colorCount]; - this declares a variable local to the testApp::setup function. Maybe you accidentally declared your member variables as int? — user529758
– user529758, Commented Feb 26, 2013 at 22:27
Please stop using new[] and switch to a standard container like std::vector. — Qaz
– Qaz, Commented Feb 26, 2013 at 22:30
Right, like I said I'm moving into C++ from Java. new[] is standard notation for Java. I will try that and see if it helps. — amoeboar
– amoeboar, Commented Feb 26, 2013 at 22:34
Use std::vector for dynamically signed arrays. Raw pointers to dynamically allocated objects usually lead to trouble. — juanchopanza
– juanchopanza, Commented Feb 26, 2013 at 22:36
Ok, I would like to adopt the best coding practices. How can I implement the std::vector into my code? — amoeboar
– amoeboar, Commented Feb 26, 2013 at 22:51

ryanbwork · Accepted Answer · 2013-02-26 22:35:50Z

0

Looks like you're allocating space for the arrays in the setup() function, but your pointers are defined locally and as such go out of scope as soon as the function has finished execution; when you try and reference them in the draw() function you're getting a compiler error because the symbols aren't found/aren't defined correctly. Move the int *hueValues/saturationValues/brightnessValues declarations into the private section of the testAPP header file, keep the allocation code (new int[coloCount]) in the setup function, and then you should be able to reference the arrays in the draw() function without an error.

testApp.h:

private:
int* hueValues;
int* saturationValues;
int* brightnessValues;

testApp.cpp

void testApp::setup(){
  hueValues = new int[colorCount];
  ...
}

edited Feb 26, 2013 at 22:35

answered Feb 26, 2013 at 22:30

ryanbwork

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2 Comments

amoeboar Over a year ago

That seemed to remove the errors from my setup() function, but now the errors in draw() simply say: "At this point in file" and don't give me much information for debugging. They systematically seem to appear whenever I try to assign a random value to the the array I've initialized. For instance, at: hueValues[i] = (int) random(0,360);

ryanbwork Over a year ago

Where is random defined? Can you provide the full compilation error?

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