R

RAM is an acronym for Random Access Memory. This is the working storage of a computer, where data and programs are stored while we're using them.

Recursion: see recursion.

A reference is an identifier that acts as another name for an existing variable rather than as an independent variable. Changing a reference therefore affects the corresponding variable. In this book, we use references only for passing arguments to functions.

A reference argument is another name for a variable from a calling function rather than an independent variable in the called function. Changing a reference argument therefore affects the corresponding variable in the calling function. Compare with value argument.

The reference-counting idiom is a mechanism that allows one object (the “reference-counted object”) to be shared by several other objects (the “client objects”) rather than requiring a separate copy for each of the client objects.

A register is a storage area that is on the same chip as the CPU itself. Programs use registers to hold data items that are actively in use; data in registers can be accessed within the time allocated to instruction execution rather than the much longer times needed to access data in RAM.

Regression testing means running a modified program and verifying whether previously working functionality is still working.

A regular member function is any member function that is not in any of the following categories:

A derived class inherits all regular member functions from its base class.

A retrieval function is a function that retrieves data that may have been previously stored by a storage function or that may be generated when needed by some other method such as calculation according to a formula.

A return address is the memory address of the next machine instruction in a calling function. It is used during execution of a return statement in a called function to transfer execution back to the correct place in the calling function.

A return statement is used by a called function to transfer execution back to the calling function. The return statement can also specify a value of the correct return type for the called function. This value is made available to the calling function to be used for further calculation. An example of a return statement is return 0;, which returns the value 0 to the calling function.

A return type tells the compiler what sort of data a called function returns to the calling function when the called function finishes executing. The return value from main is a special case; it can be used to determine what action a batch file should take next.

A return value is the value returned from a called function to its calling function.

ROM is an abbreviation for Read-Only Memory. This is the permanent internal storage of a computer, where the programs needed to start up the computer are stored. As this suggests, ROM does not lose its contents when the power is turned off, as contrasted with RAM.

Run time means “while a (previously compiled) program is being executed”.

The run-time type of a variable is the type that variable has when the program is being executed. In the presence of polymorphism, this type may differ from the type with which the variable was declared at compile time.