Computer Science

• Data type

  The basic data types provided by a programming language as building blocks. Most languages allow more complicated composite types to be recursively construction starting from basic types. E.g. char, integer, float, Boolean.
• String


  A sequence of alphanumeric characters and or symbols. e.g. a word or sentence.
• Integer


  A data type used to store positive and negative whole numbers.
• Real / float


  A data type used to store an approximation of a real number in a way that can support a trade-off between range and precision. A number is, in general, represented approximately to a fixed number of significant digits and scaled using an exponent.
• Boolean


  Used to store the logical conditions TRUE / FALSE. Often translated to On/Off, Yes/No etc.
• Character


  A single alphanumeric character or symbol.
• Date / Time


  A special data time used to store real dates. Behind the scenes, the date and time is actually represented by a single whole integer number which is the number of seconds since January 1st 1970 00:00:00. Also known as the computing epoc.
• Pointer / Reference


  An object, who value refers to (or points to) another value store elsewhere in the computer memory using its memory address.
• Record


  A data structure which consists of a collection of elements, typically in fixed number and sequence and typically indexed by names. The elements of records may also be called fields.
• Array / List


  A set of data items of the same type grouped together using a single identifier. Each of the data items is addressed by the variable name and a subscript.
• User defined data type

  A user-defined data type (UDT) is a data type that derived from an existing data type. You can use UDTs to extend the built-in types already available and create your own customized data types.
• Assignment


  An assignment statement sets and/or re-sets the value stored in the storage location(s) denoted by a variable name; in other words, it copies a value into the variable. In most imperative programming languages, the assignment statement (or expression) is a fundamental construct.
• Subroutine


  A set of instructions designed to perform a frequently used operation within a program.
• Sequence


  One of the 3 basic programming constructs. Instructions happening one after the other in order is sequence.
• Selection


  One of the 3 basic programming constructs. Instructions which can evaluate a Boolean expression and then branch the code to one or more alternatives paths is branching / selection.
• Iteration


  One of the 3 basic programming constructs. A selection of code which can be repeated either a set number of times (count controlled) or a variable number of times based on the evaluation of a Boolean expression (condition controlled) is iteration.
• Count controlled loop


  An iteration which loops a fixed number of times. The count is kept in a variable called an index or counter. When the index reaches a certain value (the loop bound) the loop will end. Count-controlled repetition is often called definite repetition because the number of repetitions is known before the loop begins executing.
• Condition controlled loop


  A way for computer programs to repeat one or more various steps depending on conditions set either by the programmer initially or real-time by the actual program.
• Integer division


  Integer division is division in which the fractional part (remainder) is discarded. It is sometimes denoted by \ symbol. Note this is different from normal division which is denoted by /.
• ==


  A mathematical comparison operator which means 'the same as', often referred to as equality
• !=


  A mathematical comparison operator which means not equal to, sometimes <> is used instead.
• <


  A mathematical comparison operator which means less than.
• >


  A mathematical comparison operator which means greater than.
• <=


  A mathematical comparison operator which means less than or equal to.
• >=


  A mathematical comparison operator which means greater than or equal to.
• NOT


  A logical operator used within a program. NOT works by returning FALSE if the input is TRUE, and returning TRUE if the input is FALSE.
• AND


  A logical operator used within a program. AND works by only returning TRUE if both values being compared are TRUE.
• OR


  A logical operator used within a program. OR works by returning TRUE as long as either value being compared is TRUE.
• XOR


  A logical operator used within a program. XOR stands for exclusive OR. It will return TRUE if the two items being compared are different.
• Variable


  A value that can change, depending on conditions or on information passed to the program.
• Constant


  A value that cannot be altered by the program during normal execution, i.e., the value is constant.
• String operation: Length


  An operation available in most programming languages which can be performed in a string data type: It returns the length of the string as an integer.
• String operation: Position


  An operation available in most programming languages which can be performed in a string data type: It returns the position of a character you provide in another string you provide.
• String operation: Substring


  An operation available in most programming languages which can be performed in a string data type: It returns substring of the first argument starting at the position specified in the second argument and the length specified in the third argument.
• String operation: Concatenation


  An operation available in most programming languages which can be performed in a string data type: It joins two separate string data types together into a single new string.
• String operation: Character character code

  An operation available in most programming languages which can be performed in a string data type: It takes in a single character such as the ASCII value 'A' and returns the relevant ASCII integer code e.g. 65.
• Exception handling


  The process of responding to occurrences of anomalous or exceptional conditionals during the normal flow of program execution.
• Parameter


  Data structures passed into a Procedure or Function when they are initially called.
• Procedure


  A block of code given a unique identifiable name within a program. A procedure can take either zero or more parameters when it is called. The procedure should be designed and written to perform one task or action which is clearly indicated by its name.
• Function


  A block of code given a unique identifiable name within a program. A function can take either zero or more parameters when it is called and should return a value. The function should be designed and written to perform one task or action which is clearly indicated by its name.