load images into an array then draw them according to key presses

imageLauncher.cpp

// use this way of definining size to establish your array globally
#define NUM_IMAGES 4

// create an array of images
ofImage question[NUM_IMAGES];

int imgCounter;
int imgAlteration;

void setup() {
	// put your setup code here, to run once:
	ofSetWindowShape(800,600);
	imgAlteration = 120;
	// load the images into the array
	// file names should be numbers so the images should be named: "1.jpg" "2.jpg" "3.jpg" etc.
	for(int i = 0; i < NUM_IMAGES; i++) {
	    string curImg = ofToString(i);
	    curImg += ".jpg";
	    question[i].loadImage(curImg);
	}
	
}

void draw() {
	// put your main code here, to run once each frame:
    ofSetColor(imgAlteration);
	question[imgCounter].draw(0, 0, ofGetWindowWidth(), ofGetWindowHeight());
}

void keyPressed(int key)
{
    if('y' == key)
    {
        // conditional to loop back around to the first image
        if(imgCounter == (NUM_IMAGES-1) ){
            imgCounter = 0;
        } else {
            imgCounter++;
        }
        if (imgAlteration < 255){
            // add 5 each time the y key is pressed
            imgAlteration +=5;
        }
        
    }
    
    if('n' == key)
    {
        if(imgCounter == (NUM_IMAGES-1) ){
            imgCounter = 0;
        } else {
            imgCounter++;
        }
        if (imgAlteration > 0){
            // subtract 5 each time the n key is pressed
            imgAlteration -=5;
        }
    }
    
}