There is a lot of timers around in the forum, this is one is an example I've made for some other topic, it may help...

That's fairly easy.

use mills()

see reference.


idea is :
At the start of the program save the time in a var. When solved, save the time in another var. The difference gives you the time passed.


What to do:
before setup()

1. int startAtProgramBegin;

in setup() (at the end of it) where program starts say

1. startAtProgramBegin = millis();

in draw()

1. if (puzzleIsSolved) {
2.    int startAtSolved = millis();
3.    println("You solved it in " + ((startAtSolved - startAtProgramBegin) / 1000.0) + " seconds. Congratulations!" );
4. }

A small complete program to test this:

1. int startAtProgramBegin;
2. int startAtSolved=0;
3. 
   
4. void setup() {
5.   startAtProgramBegin = millis();
6. }
7. 
   
8. void draw() {
9. 
   
10.   if (keyPressed&&startAtSolved==0) {
11.     startAtSolved = millis();
12.     println("You solved it in "
13.       + ((startAtSolved - startAtProgramBegin) / 1000.0)
14.       + " seconds. Congratulations!" );
15.   }
16. 
    
17. }

Thank you so much guys!  Greatly appreciated.