public Song transposeSong(){
        //this method creates a temporary song based on the chordpro format of the selected song except transposing the chords
        // by the specified amount and then returns the transposed song
        ArrayList<String> transposedChordProLines = new ArrayList<String>();
        boolean atChord = false;
        boolean skipChar = false;
        String keysSharp[] = {"A", "A#", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#"}; //arrays to store all 12 keys
        String keysFlat[] = {"A", "Bb", "B", "C", "Db", "D", "Eb", "E", "F", "Gb", "G", "Ab"};
        for(int i = 0; i < chordProLines.size(); i++){
            String transposedLine = "";
            for(int j = 0; j < chordProLines.get(i).length(); j++){
                if (skipChar == true){
                    skipChar = false;
                }
                else if(chordProLines.get(i).charAt(j) == '['){
                    atChord = true;
                    transposedLine += chordProLines.get(i).charAt(j);
                }
                else if(chordProLines.get(i).charAt(j) == ']'){
                    atChord = false;
                    transposedLine += chordProLines.get(i).charAt(j);
                }
                else if(atChord == true){
                    if(chordProLines.get(i).charAt(j) == 'A' || chordProLines.get(i).charAt(j) == 'B' || chordProLines.get(i).charAt(j) == 'C' || chordProLines.get(i).charAt(j) == 'D' || chordProLines.get(i).charAt(j) == 'E' || chordProLines.get(i).charAt(j) == 'F' || chordProLines.get(i).charAt(j) == 'G'){
                        String currentKey = Character.toString(chordProLines.get(i).charAt(j));
                        if(chordProLines.get(i).charAt(j+1) == 'b' || chordProLines.get(i).charAt(j+1) == '#'){
                            currentKey += Character.toString(chordProLines.get(i).charAt(j+1));
                        }
                        for(int k = 0; k < 12; k++){
                            if(currentKey.equals(keysSharp[k])){
                                transposedLine += keysSharp[(k + transpositionIndex) % 12];
                                if(currentKey.length() > 1){
                                    skipChar = true;
                                }
                                break;
                            }
                            else if(currentKey.equals(keysFlat[k])){
                                transposedLine += keysFlat[(k + transpositionIndex) % 12];
                                if(currentKey.length() > 1){
                                    skipChar = true;
                                }
                                break;
                            }
                        }
                    }
                    else{
                        transposedLine += chordProLines.get(i).charAt(j);
                    }
                }
                else {
                    transposedLine += chordProLines.get(i).charAt(j);
                }
            }
            transposedChordProLines.add(transposedLine);
        }
        Song transposedSong = new Song(getSongTitle(), transposedChordProLines);
        //transposedSong.printToConsole();
        return transposedSong;
    }