Learn

GNU Octave was started in 1988 to teach undergrad numerical methods. Today it's a full open-source MATLAB alternative — with the same syntax, mostly compatible toolboxes, and a thriving community.

disp("Hello, Octave!")

• disp(x) writes x followed by a newline
• printf("format", args) for C-style formatted output
• Comments use % or # (both work)
• Statements end with newline; suppress output (when assigning) with trailing ;
• Double-quoted strings interpret escapes ("a\nb" is two lines); single-quoted ones do not ('a\nb' keeps a literal backslash and n). Format strings therefore want double quotes.

Reading stdin: input("") reads a value from stdin. With second arg "s" it reads as a string:

n = input("")           % reads as a number
line = input("", "s")   % reads as a string

disp is not printf

Both write to stdout, but they are not interchangeable. disp formats a value the way the interactive prompt would, and for a number that means leading whitespace. printf writes exactly the characters your format string asks for and nothing else.

disp("hi")                % hi
disp(7)                   %  7      <- note the leading space
printf("%d\n", 7)         % 7

Use disp for text you are printing literally, and printf whenever a number has to land in an exact position. Graded output is compared character by character, so a stray leading space is a wrong answer.

One more habit to build now: a statement with no trailing semicolon echoes its result, variable name and all.

x = 5      % prints "x =  5"  (yes, two spaces - it is the prompt format)
x = 5;     % prints nothing

That echo goes to stdout like any other output, so a forgotten semicolon in an exercise shows up as extra lines the grader never asked for.