208.Assignment Operator Overloading (C++ Only)

1316 ワード

Implement an assignment operator overloading method.
Make sure that:
The new data can be copied correctly The old data can be deleted/free correctly. We can assign like A = B = C
Clarification This problem is for C++ only as Java and Python don't have overloading for assignment operator.
Example If we assign like A = B, the data in A should be deleted, and A can have a copy of data from B. If we assign like A = B = C, both A and B should have a copy of data from C.
//copy answer from jiuzhang
class Solution {
public:
char *m_pData;
Solution() {
    this->m_pData = NULL;
}
Solution(char *pData) {
    if (pData) {
        m_pData = new char[strlen(pData) + 1];
        strcpy(m_pData, pData);
    } else {
        m_pData = NULL;
    }
}

// Implement an assignment operator
Solution operator=(const Solution &object) {
    if (this == &object) {
        return *this;
    }
    
    if (object.m_pData) {
        char *temp = m_pData;
        try {
            m_pData = new char[strlen(object.m_pData)+1];
            strcpy(m_pData, object.m_pData);
            if (temp)
                delete[] temp;
        } catch (bad_alloc& e) {
            m_pData = temp;
        }
    } else {
        m_pData = NULL;
    }
    return *this;
}
};