Object Oriented Programming:Encapsulation

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Encapsulation

Encapsulation (or "information hiding") is the process of hiding the data structures of the class and allowing changes in the data through a public interface where the incoming values are checked for validity.

[edit]

Example in C++

// An example unit class
class CUnit
{
private:
	int m_iHealth;
 
public:
	CUnit();
	virtual ~CUnit();	
 
	void SetHealth( int iHealth );
	int  GetHealth();
};
 
CUnit::CUnit()
{
	// Set the health variable to the its default value
	m_iHealth = 100;
}
 
CUnit::~CUnit()
{
	// The class is unloading
}
 
void CUnit::SetHealth( int iHealth )
{
	// Here we use the new health value that has been provided
	// but we make sure that the value is valid, and we have
	// the oppotunity to handle the situation where an invalid
	// value has been passed.
 
	// If the health is below zero
	if ( iHealth < 0 ) 
	{
		m_iHealth = 0;
		// Trigger a function to kill the unit
	} 
	// If the health is above 100
	else if ( iHealth > 100 ) 
	{
		m_iHealth = 100;
		// The player is cheating, ban their game account!
	} 
	// The passed health value is between 1 and 100 and is valid
	else 
	{
		m_iHealth = iHealth;
	}
}
 
int CUnit::GetHealth()
{
	// Returns the value of the health variable
	return m_iHealth;
}