02 NES BASIC PROGRAMMING GUIDE
Quick start: type, run, keep
In the browser, open the playground. The actual cartridge boots and prints its welcome and READY. In the iOS app, open NDB SOFTWARE, choose NES BASIC, then PLAY / RESUME. Press Select to open the on-screen keyboard. Move with the D-pad, insert with A, backspace with B and submit with Start. On an external keyboard, type normally and use Enter. Submit each numbered line separately.
10 PRINT "HELLO FROM NES BASIC"
20 ENDNow submit RUN. The output is HELLO FROM NES BASIC. Submit LIST to see the two stored lines. A number at the start stores a line; an unnumbered submission is a direct command. The number is an address in your program, not part of the printed message. Leaving gaps of ten makes it easy to insert lines later.
To change the message, resubmit line 10 with a different quoted string. To delete line 20, submit 20 by itself. The editor is a line editor, not a full-screen source editor: LIST displays stored code, and you replace a stored line by typing its number and new contents. Source is kept sorted by line number.
Submit SAVE "HELLO" and wait for SAVED "HELLO". After a cold start, use LOAD "HELLO", then RUN. RUN "HELLO" loads and runs the named file in one step. If a confirmation appears, A/Y/Enter accepts; B/N/Select/Escape cancels. A saved file includes your program and all kept BASIC artwork.
READY is printed at startup. Successful ordinary commands return quietly to the editing cursor; the lack of another READY message is normal. Errors show a message and return to editing. For a runtime error, IN 100 identifies the source line where execution failed. Correct that line and try RUN again.