How to create a program that repeats itself?

I want this program to repeat itself after giving an output (ask input again and calculate again). I don't know how to do that can someone help me?

t=36;  %total number of lectures
b=0;
while b==0
p=input('Enter Number of Lectures Attended \n');
if p>36
fprintf('Error, note that the total number of lectures are 36. \n')
else
    b=1;
end
end
a=(p/t)*100; % this calculates the percentage attendance
if a>=75
    fprintf('The student does not have short attendace. \n')
else
    fprintf('The student has short attendace. \n')
end

Answer 1

[Image Analyst]

Try this:

% Demo by Image Analyst.
clc;    % Clear the command window.
fprintf('Beginning to run %s.m ...\n', mfilename);
close all;  % Close all figures (except those of imtool.)
clearvars;
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 16;

buttonText = '';
totalNumberOfLectures=36;  % Total (max) number of lectures
while ~contains(buttonText, 'Quit', 'IgnoreCase', true)
	numLecturesAttended = -1; % Initialize
	while numLecturesAttended < 0 || numLecturesAttended > totalNumberOfLectures
		numLecturesAttended=input('Enter Number of Lectures Attended : ');
		if numLecturesAttended < 0 || numLecturesAttended > totalNumberOfLectures
			fprintf('Error. Note that the total number of lectures is %d.\nEnter a number between 0 and %d (inclusive).\n', ...
				totalNumberOfLectures, totalNumberOfLectures)
		end
	end
	percentAttended = (numLecturesAttended/totalNumberOfLectures) * 100; % This calculates the percentage attendance
	if percentAttended >= 75
		fprintf('The student does not have short attendance. \n')
	else
		% Did not attend at least 75% of their classes.
		fprintf('The student has short attendance. \n')
	end
	
	% See if they want to do another one.
	promptMessage = sprintf('Do you want to ask again,\nor Quit processing?');
	titleBarCaption = 'Continue?';
	buttonText = questdlg(promptMessage, titleBarCaption, 'Yes - Ask Again', 'No - Quit', 'Yes - Ask Again');
	if contains(buttonText, 'Quit', 'IgnoreCase', true)
		break;
	end
end
fprintf('Done running %s.m\n', mfilename);