Glossary

A | B | C | D | E | F | G | H | I | K | L | M | N | O | P | R | S | T | U | V

## A

Argument
One of the values that a command acts on.
Array
A collection of numeric variables arranged in a list or matrix for processing by the calculator. Each element in an array is referenced by its index - position in the array.
ASCII
The American Standard Code of Information Interchange. It uses 1 byte (8 bits) to hold a character, and thus is limited to 256 different characters. The calculator uses a modified version of ASCII internally to store characters (see Character Codes), but the TI-Basic interpreter deals with tokens instead.
Assembly
The other programming language built-in to the TI graphing calculators, apart from TI-Basic. It is much more difficult to learn and program in, but at the same time it is much more powerful, and can be used to create very sophisticated games and programs. You can also compile C into an assembly program.

## B

Binary
The two-digit (bit) number system based on 0 and 1, similar to the way the normal decimal system is based on the numbers 0-9. For example the number 10101 in binary represents 1*24+0*23+1*22+0*2+1, or 21 in decimal. To enter a number in binary on a TI-68k calculator, write 0b followed by the number.
Bit
A binary digit (0 or 1).
Branch
A departure from the sequential performance of program statements. An unconditional branch causes the calculator to jump to a specified place in the program each time the branching statement is encountered. A conditional branch transfers program control based on the result of some logical condition.
Breakpoint
A point in a program where program execution can be suspended, used when debugging the program. In TI-Basic, such breakpoints can be created with the Text command.
Bug
Byte
A string of eight bits. The calculator uses one byte of information to encode the letter "A", as well as most tokens. Bytes (or kilobytes - one kilobyte is 1024 bytes) are used to measure the amount of memory a program or variable takes up on the calculator.

## C

C
A popular programming language on many platforms. Using TIGCC, C programs can be compiled to assembly for the TI-68k calculators.
Character
A letter, number, punctuation symbol, or special graphics symbol. They are encoded in ASCII format internally, but the TI-Basic interpreter uses tokens instead.
Clock cycle
The unit of time in a CPU. It is so small that even the most primitive assembly instructions take several clock cycles to run; the amount of clock cycles it takes for a single TI-Basic command can be in the millions.
Command
A word or token that tells the calculator to do something. Examples: RclPic, For, max(), etc. They are sometimes subdivided into functions and instructions
Concatenation
Joining two or more strings together to make a longer string. The ampersand — & — is the concatenation operator. For example, "TI-"&"Basic"="TI-Basic".
Condition
A logical expression that the calculator can evaluate to be true or false.
Constant
A specific number, list, matrix, or string that is given as a fixed value in the program (such as 9.024 or "Hello"), rather than contained in a variable.
CPU (Central Processing Unit)
The "brain" of the calculator, where the calculator controls the processing and execution of everything.
Cursor
A small, flashing square showing where a typed character will appear. A cursor (in the form of a crosshair) is also used on the graph screen to input a point from the user.

## D

Data
Information, often numerical in form. When data is used by a calculator program, it can be hardcoded or softcoded.
Debugging
Fixing a program to remove bugs, or mistakes. There are many techniques for debugging, some universal, some specific to calculator programming.
Decimal
A base 10 number system using the symbols 0-9. It is the default number system used by the calculator.
Default
A standard characteristic or value which the calculator assumes without specification. For example, the RclPic displays a picture at the coordinate (0,0) by default (the top left corner). This can be overwritten with further arguments to specify the coordinate to display at.
Dialog
A message box displayed on the screen for input and output.

## E

Execute
Another name for running a program or command.
Exponent
A number indicating the power to which a number or expression is to be raised, usually written at the right and above the number. For example, 26 = 2x2x2x2x2x2. In scientific notation, the power of ten which the mantissa is multiplied by to calculate the actual number.

## F

Flash
The ROM/archive memory on the TI-68k calculators where applications are stored.
Floating point
The format used in TI-Basic for storing decimals. It uses scientific notation to display all numbers.
Flow Chart
A diagram of geometric shapes connected by arrows that show the progression of a program. Flow charts are handy for developing complicated programs and illustrating how programs work.
Function
The word Function has several meanings in the context of TI-Basic programming. It can mean a type of command that returns a value - such as gcd() or sin(). Or it can mean a type of user-defined program that returns a value.

## G

Graphics
Any sort of visual display on the screen, such as graphs, patters, and drawings, both stationary and animated.

## H

Hardcode
Hardcoded data is information used by the program that results from the logic of its commands. It is very easy for the program to read, but can be impossible to change.
Hardware
The circuit boards and other electronic parts which make up a calculator.
A base 16 number system using 16 symbols, 0-9 and A-F. It is used as a convenient shorthand way to express binary code, because every four bits of binary have a corresponding hexadecimal symbol. To enter a number in hexadecimal on a TI-68k calculator, write 0h followed by the number.

## I

Index
A position in an array. In TI-Basic, arrays are indexed starting with 1 (so that the first element in a list is numbered 1, the second 2, and so on). In some other languages, they are indexed starting with 0.
Input
The means by which data is entered into the calculator by the user, primarily through the calculator's keys (though the link port is also a form of input).
Instruction
In the case of TI-Basic programming, this is often used to indicate a type of command that does not return a value, but stands alone: for example, Line, or Input. It is also sometimes used to describe commands in general.
Integer
A whole number, positive or negative (or 0). Usually in TI-Basic, a number is an integer by default, which means all of its digits are stored exactly. You can also use floating point numbers for approximate calculations with decimals.
Interpreter
The algorithm stored inside the calculator that runs a TI-Basic program by executing the appropriate system routines.
Iteration
One repetition of a loop. For certain commands, the calculator has an internal loop for which the total number of iterations is relevant, and affects accuracy.

## K

The panel of keys used to enter programs and data into the calculator.

## L

List
A sequence of variables which can be accessed and modified by their position. In TI-Basic, lists can have any mix of variable types.
Loop
A group of one or more consecutive program lines which are performed repeatedly, either a specific number of times, or until a condition is met.

## M

Mantissa
The basic numeric portion of a number expressed in scientific notation. In 3.264E + 4, the mantissa is 3.264.
Matrix
A two-dimensional grid of variables which can be accessed and modified by their position. In TI-Basic, lists can have any mix of variable types.
Memory
The two different places (RAM and ROM) where calculator programs and data are stored. All variables and programs take up part of memory to store, which makes the size of a program or variable very important.
MHz
The speed the calculator CPU runs at. It ranges from 10MHz to 16MHz on the TI-68k calculators. It's measured in millions of clock cycles per second.

## N

Number system
A way of writing down a number. Two common systems used by people are the decimal (Arabic) system, and the Roman numeral system. The calculator uses the binary system internally, but the decimal system is what it usually displays.

## O

Operator
A symbol used in calculations (numeric operators) or in relationship comparisons (related operations). The math operators are +, -, *, /, ^. The relational operators are >, <, =, ≥, ≤, ≠. The logic operators are and, or, xor, not.
Optimization
The process of improving the running time, length, or memory usage of a program.
Output
Information sent from the calculator, e.g. graphics on the screen. Also, the means by which data leaves the calculator, through either the link cable, graph link, or USB cable.
OS (Operating System)
The internal program that runs the calculator and includes all the functionality needed to use the calculator.

## P

Program
The list of instructions that tells the calculator what to do to perform a task.
Programmer
A person who writes programs.
Programming Language
Numeric or alphabetic commands which the calculator can understand, and execute.

## R

RAM (Random Access Memory)
A temporary memory, i.e. one in which data is stored so long as electrical power is applied. Data in RAM can be accessed or changed and is lost if the batteries are removed from the calculator.
Recursion
A program that calls itself as a subroutine (or a function that's defined in terms of itself). See recursion.
Certain instructions for the calculator are permanently stored in ROM and can be accessed but cannot be changed. Data in ROM is not lost if batteries are removed.

## S

Scientific Notation
A method of expressing very large or very small numbers by using a base number (mantissa) times ten raised to some power (exponent).
Scroll
Shifting part of the screen to give the illusion of seeing only part of an image larger than the screen.
Softcode
Softcoded data is information stored in an array at the beginning of the program, and read from it later. It is usually slower to read than hardcoded data, but the advantage is that the same code can often used for different data stored in the same way.
Sprite
A small image which is moved around the screen using code and/or repeated multiple times on the screen.
Statement
A single line of a program containing a single instruction such as Text, RclPic, max(), etc. Usually synonymous with command.
String
A variable type that stores text as a series of characters.
Subprogram
A program segment which can be used more than once during the execution of a program, such as a complex set of calculations or a print routine. You can make subprograms using the Define command.

## T

TI (Texas Instruments)
The makers of the TI graphing calculators. In addition to graphing calculators, they also make a large assortment of other electronic devices.
TI-68k
The unofficial name for the TI calculators that have a 68k processor: the TI-89, TI-89 Titanium, TI-92, TI-92 Plus, and Voyage 200. These are the calculators described in this section of TI|BD.
TI-Basic
The unofficial name of the programming language found on TI calculators.
Token
A single instruction or symbol in tokenized TI-Basic that takes up 1 to 3 bytes and is used to encode TI-Basic programs.

## U

User
When talking about the effect of a program or command, it is the person running the program or command on his/her calculator.

## V

Variable
A name given to a value which may vary during program execution. A variable is a memory location where values can be replaced by new values during program execution.