CSE 232 SS13 Lab 4 Notes


1. Arguments and Parameters

Formal argument -- the name used within a function definition
Actual argument -- variable or constant used in a function call

Parameter = formal argument
Argument = short for "actual argument"



2. Value and Reference paramters

A.k.a. "pass by value" and "pass by reference".

Value parameters are *copies* -- changes to these variables they do not affect the argument, which can be a constant or a variable.

Reference parameters (marked with "&") are not copies. The parameter inside the function names the same memory location as the variable that was given as an argument, which must be a variable.

	/* params.h */

	void f(int x);
	void g(int x);
	
	
	
	/* params.cpp */
	
	void f(int x) {
		x = 100;
	}
	
	void g(int & x) {
		x = 100;
	}
	
	
	
	/* driver.cpp */
	
	#include "params.h"
	
	int main {
		int x = 5;
		
		f(x); // x is still 5
		g(x); // x is now 100
	}

	
	
3. Uses of Reference Parameters

a. Method for multiple return values
	
	ex.
	void f(int & a, int & b, int & c) {
		...
	}

b. Most efficient way to pass class objects, since copying large objects takes time