Editing MBASIC (section)

=== Variables and data types ===
MBASIC supported the following data types:
* 8-bit character data, in strings of length 0 to 255 characters;
* 16-bit [[integer]]s;
* 32-bit [[floating point]] (single precision), equivalent to six decimal digits, with a two-digit exponent;
* 64-bit floating point (double precision), equivalent to sixteen decimal digits, with a two-digit exponent.

String operators included substring selection, concatenation, assignment, and testing for equality.

Arrays of the above types were allowed with up to 7 dimensions, but no functions or operators worked on arrays; for example, there was no assignment of arrays. Unlike some other BASIC implementations of the time, MBASIC did not provide support for [[matrix (mathematics)|matrix]] operations, [[complex number]]s, or a [[binary-coded decimal|decimal (BCD)]] data type for financial calculations. All floating point operations were carried out in software since typical CP/M systems did not have [[floating-point unit|floating point hardware]]. The built-in mathematics functions ([[sine and cosine|sine, cosine]], [[tangent]], [[natural logarithm|natural log]], [[exponential function|exponential]], [[square root]]) only gave single precision results. A software [[pseudorandom number generator]] was provided; this relied on the user to key in a seed number to obtain a sequence of numbers useful for games and some simulations. MBASIC permitted but did not require the <code> LET </code> keyword for assignment statements.

Early versions of BASIC on [[microcomputer]]s were infamous for one- or two-character variable names, which made the meanings of variables difficult to recall in complex programs. MBASIC version 5 allowed identifiers up to 40 characters long, which permitted programmers to give variables readable names.