private void materialRaisedButton1_Click(object sender, EventArgs e)
 {
     //if(validationString.ElementAt(currStringIndex))
     if (validationString.Length > 0)
     {
         targetArrow = null;
         if (currentState != null)
         {
             foreach (Arrow arrow in currentState.exitArrowList)
             {
                 foreach (String str in arrow.getDelta())
                 {
                     if (str.CompareTo("" + validationString[currStringIndex]) == 0)
                     {
                         targetArrow = arrow;
                         break;
                     }
                 }
                 if (targetArrow != null)
                 {
                     break;
                 }
             }
         }
         if (targetArrow != null)
         {
             currentState = targetArrow.toState;
         }
         else
         {
             currentState = null;
         }
         if (currentState == null)
         {
             materialRaisedButton1.Enabled = false;
             displayMessageBox("String not accepted");
         }
         else
         {
             if (materialCheckBox1.Checked)
             {
                 speech.Speak(targetArrow.fromState.stateName + " on " + Char.ToUpper(validationString[currStringIndex]) + " goes to " + targetArrow.toState.stateName);
             }
             processedString = processedString + validationString[currStringIndex];
             if (currStringIndex + 1 != validationString.Length)
             {
                 currStringIndex++;
             }
             else if (currentState.final)
             {
                 materialRaisedButton1.Enabled = false;
                 displayMessageBox("String accepted");
             }
             else
             {
                 materialRaisedButton1.Enabled = false;
                 displayMessageBox("String not accepted");
             }
         }
         drawPanel1.Invalidate();
     }
 }