IB Computer Science Topic B2.1: Programming Fundamentals Key Definitions

A marker set on a line of code that makes a debugger pause the program just before that line runs, so the value of every variable in scope can be read.

Concatenation is joining two or more strings end to end to produce one new, longer string.

The process of locating the cause of incorrect program behaviour and then removing it. Locating the cause is separate from, and usually harder than, correcting it.

A delimiter is the character or sequence of characters that marks the boundary between fields inside one string, such as the comma in a line read from a CSV file.

An error condition raised while a program is running, in code that started up without fault. It interrupts the normal flow of execution at the statement that raised it, and the program either handles it or stops there.

The block of code that runs in place of the normal flow when a matching exception is raised. It is written as a catch clause in Java and an except clause in Python, and each one names the exception type it responds to.

Immutability means a value cannot be changed once it has been created. Strings in Java and Python are immutable, so every string operation returns a new string and leaves the original one as it was.

A fault that lets a program translate and run to completion but produce an incorrect result. No error message is reported, so only testing against an expected output reveals it.

The report a runtime prints when an exception is left unhandled, naming the exception type, the statement that raised it, and the sequence of method calls that led to that statement.

A substring is a portion of a string, obtained using an index or slicing operation.

A table used to record what happens as an algorithm is executed by hand, with a column for the step, a column for the action, and one column for every variable. A new row is written whenever a value changes.

A named storage location in memory that holds one value at a time. Assigning a new value to the name replaces the value already stored there.

The region of a program in which a variable's name can be used. A global variable has the whole program as its scope; a local variable has only the function or method that declares it.