Editing Dartmouth BASIC (section)

===First Edition===
The original version, retroactively known as version one, supported the commands <code>LET</code>, <code>PRINT</code>, <code>END</code>, <code>FOR...NEXT</code>, <code>GOTO</code>, <code>GOSUB...RETURN</code>, <code>IF...THEN</code>, <code>DEF</code>, <code>READ</code>, <code>DATA</code>, <code>DIM</code>, and <code>REM</code>. It included basic math instructions, {{key|+}}, {{key|-}}, {{key|*}} and {{key|/}}, as well as the up-arrow for exponents "...since on a teletype typewriter it is impossible to print superscripts."{{sfn|Kurtz|1981|p=523}} In modern varieties, the up-arrow is normally replaced by the "hat" character, {{key|^}}. Exponents took the absolute value of the number before calculation, so to calculate {{code|-X^3}}, one had to use {{code|X*X*X}}. There was a further problem in the exponent function that treated {{code|-X^2}} as {{code|(-X)^2}} as opposed to the correct [[order of operations]] {{code|-(X^2)}}, which was not corrected until the third release.{{sfn|Kurtz|1981|p=523}} The <code>INT()</code> function always truncated towards zero.{{sfn|Kurtz|1981|p=524}}

The language had a number of idiosyncrasies of its own. In contrast to later versions, the <code>LET</code> command was required on all statements lacking another command, so {{code|2=basic|1=10 A=5*5}} was not valid in this version.{{sfn|Kurtz|1981|p=524}} The <code>PRINT</code> statement used the comma when printing multiple variables, advancing to the next of five "zones". The comma was not needed in the case where one was printing a prompt and single value, so {{code|2=basic|PRINT "value of A is "A}} was valid. A somewhat hidden feature was that all variables were capable of representing arrays (vectors) of up to ten elements (subscripts 1 to 10, changed to 0 to 9 in the Second Edition) without being declared that way using <code>DIM</code>. <code>DIM</code> was only needed if a different vector size was required.{{sfn|Kurtz|1981|p=525}}{{efn|This feature was found on most BASICs based on Dartmouth, but was rare on those that were created independently.}}

Variable names were limited to a single letter or a letter followed by a digit (286 possible variable names). User functions could only have a single letter, thus {{code|FNA}} through {{code|FNZ}}. All operations were done in [[floating point]]. On the GE-225 and GE-235, this produced a precision of about 30 bits (roughly ten digits) with a base-2 exponent range of -256 to +255.<ref>{{cite web|last=Kurtz|first=Thomas|title=BASIC Commands: The Original-Original Version|url=https://www.dartmouth.edu/basicfifty/commands.html#:~:text=All%20arithmetic%20was%20done%20in,of%20%2D256%20to%20%2B255.&text=Ten%20numeric%20functions%20were%20provided.}}</ref>

Additionally, due to the GE-235's word size being 20-bits and using a [[six-bit character code]], the language enshrined the use of three-letter function names because that allowed the storage of three six-bit characters in a 20-bit word (using 18 bits). This is why BASIC functions are three letters, like <code>INT</code> or <code>SQR</code>, something that remained in the many varieties of the language long after they left the GE-235.{{sfn|Kurtz|1981|p=524}}