How to calculate time elapsed during some continous code?

I am applying some odometry discrete equations and i want to calculate time difference between the two steps. I am trying to use etime but it does not work. Here is part of my code

rob=setParam(); % Robot Parameters previousTime=clock;

%% Running Loop while(true)

    if count==1 
        % for Inital conditions 
       posX(count)=0;
       posY(count)=0;
       heading(count)=0;
    end 

    rpmLeftWheel=readSpeed(encoderLeft);
    rpmRightWheel=readSpeed(encoderRight); 

    currentTime=clock;
    dt=etime(currentTime,previousTime); 
    [posX,posY,heading]= computeOdometry(rpmLeftWheel,rpmRightWheel,dt,count,rob); 
    previousTime=currentTime; 
    count=count+1

Answer 1

[Abhay SAMUDRASOK]

Try tic toc in your code. It would do the job

 tic

    if count == 1 
        % for Inital conditions 
       posX (count) = 0;
       posY (count) = 0;
       heading (count) = 0;
    end 
    rpmLeftWheel = readSpeed (encoderLeft);
    rpmRightWheel = readSpeed (encoderRight); 
toc