create a popup window that says “hello!” in matlab

To create a popup window with a message in MATLAB, you can create a new GUI figure and add a static text UI component to display the message. Here's an example code block:

main.m
% create a new figure
popup = figure('Units','normalized','Position',[0.4,0.4,0.2,0.2],'MenuBar','none','ToolBar','none','NumberTitle','off','Name','Hello!');

% add a static text component with the message
uicontrol(popup,'Style','text','String','Hello!','HorizontalAlignment','center','Units','normalized','Position',[0.1,0.4,0.8,0.2],'FontSize',16,'FontWeight','bold');

% wait for the user to close the popup window
uiwait(popup);
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This code creates a new GUI figure with a message "Hello!" displayed in a static text UI component. The window has no menu bar or tool bar and does not show the figure number in the title. The uiwait function is used to block further execution of the code until the user closes the popup window.