Basis of Function

Basis of Function

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Prerequites

C++

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What is Basis of Function

At the first time, i don’t think about any design of basis. That time i just think if i need the member function, i made it.

Regardless of function, i usually make main key for easy to use. I think the more we build the main key of function, the more to be stable design.

1. Declaration: Basis of Function

class CArithmetic
{
public:
    CArithmetic();
    CArithmetic(const CArithmetic& alg);
    CArithmetic(const CArithmetic* pAlg);
    virtual ~CArithmetic();

    CArithmetic& operator=(const CArithmetic& alg);

public:
    bool Clear();
    bool Assign(const CArithmetic& alg);
    bool Assign(const CArithmetic* pAlg);
};

2. Definition: Basis of Function

CArithmetic::CArithmetic()
{
    Clear();
}

CArithmetic::CArithmetic(const CArithmetic& alg)
{
    Assign(alg);
}

CArithmetic::CArithmetic(const CArithmetic* pAlg)
{
    Assign(pAlg);
}

CArithmetic::~CArithmetic()
{
    Clear();
}

CArithmetic& CArithmetic::operator=(const CArithmetic& alg)
{
    Assign(alg);

    return *this;
}

bool CArithmetic::Clear()
{
    // implement

    return true;
}
bool CArithmetic::Assign(const CArithmetic& alg)
{
    Assign(&alg);
}

bool CArithmetic::Assign(const CArithmetic* pAlg)
{
    bool bOk = false;

    do
    {
        if(!pAlg)
            break;

        // implement

        bOK = true;
    }
    while(false);

    return bOK;
}

Constructor and Destructor is related with Clear function. The Clear function is initialization of all of class for clients included in memory deallocation and so on. But sometimes little bit difference between clear and constructor. For example, if we do not initialize member variable of pointer, it has dummy value, not null. So if the clear function contains deallocating pointer, there’s deallocation issue. Therefore we should two step for constructor, initial for member variable and call clear function.

operator= and copy constructor is same function with Assign function. So Do not implement same code using copy and paste codes, just call each other. Especially the main implementation is Assign with pointer parameter, not reference parameter. Because someone who misuses the assign function occur from Assign with pointer parameter owing to pass null as the input.