Other C++ Features

UMBC CMSC 211

Other C++ Features

Default Parameters

C++ allows a function to be declared with one or more parameters omitted, and gives them a default value:

int fun( int a, float b = 2.3, char c = 'x' );

Then the program can have:

fun( n, 3.14159 );

The compiler keeps a symbol table where it collects all of the necessary information and when one parameter is missing, it provides the value automatically, in this case with a:

push   'x'

Overloaded Functions

Since the function name can appear with different parameter types, the compiler creates a unique name (name mangling):

declaration	name/type	return	params	suffix
void f( )	?f@@YA	X	X	Z
void f( float )	?f@@YA	X	M	@Z
void f( float, float )	?f@@YA	X	MM	@Z
void f( int )	?f@@YA	X	H	@Z
int f( char )	?f@@YA	H	D	@Z
void f( int& )	?f@@YA	X	AAH	@Z
void f( int&, int& )	?f@@YA	X	AAH0	@Z
void f( int&, int&, int& )	?f@@YA	X	AAH00	@Z
void f( char &, int & )	?f@@YA	H	AADAAH	@Z

Polymorphic Call of Virtual Functions

This allows determining at run time what the data types of the argument are and the correct version of the function is called.

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