Time calculator from initial to final point

I having a project of time calculator from initial point to final point using ultrasonic sensors with rf module do I want to know how I can made a program for that which will give me the exact time .we having a formula racing car and we want to know the time of car how much time it takes to cover from initial point to final point.please give me the program for that bcoz I didn't get the proper output till yet.

Save the value of millis() when the initial point is passed
Save the value of millis() when the final point is passed
The elapsed time is the difference of the two

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please give me the program

We can't give the program, bcoz [sic] we don't know anything about your hardware or your requirements.