Thanks

#include <time.h>

in time.h there's a function named clock() which counts cpu clocks since the
beginning of your program
it also contains a constant named CLOCKS_PER_SEC
so if you divide clock() by CLOCKS_PER_SEC at the end of your code you'll
get the running time
(remember to cast the result to double to get the exact result)

cout << clock() / (double) CLOCKS_PER_SEC << endl;