What is the command to repeat the program?

So I am making an if statement, I wanted to know if there is a command that restarts the program for the user. So the program starts by asking the user for some input, if the input is invalid then it outputs that it is invalid, I want it to be that the program then restarts and asks the user again for input, so if it is valid, the user can keep going with the program.

Answer 1

[Massimo Zanetti]

Here it is:

while 1
     x = input('Enter your input: ');
     %check the input according to your needs 
     %for example here I check the input is even number
     if rem(x,2)==0
         break;
     end
end
%do whatever you want with your right input
disp('done');