c++ - 重载赋值运算符不适用于链接

Question

我想在分配新值之前进行维度检查。所以我这样做了:

矩阵.cpp

Matrix& Matrix::operator=(Matrix m){      

    // check dimensions
    if(m_rows != m.m_rows || m_cols != m.m_cols )
        fail();

    thrust::copy(d_data.begin(), d_data.end(), m.d_data.begin() );// gives error if pass in Matrix& m
    return *this;
}

矩阵.h

Matrix& operator=(Matrix m);

测试.cpp

Matrix A, B;
... initialize B as all 1's ...
A = B;       // This works
A = B * 3.0; // Wrong, A = B
B = B * 3.0; // Wrong, B does not change

如果 operator = 没有被重载，那么它是正确的:

Matrix A, B;
... initialize B as all 1's ...
A = B;       // A is all 1's
A = B * 3.0; // A is all 3's
B = B * 3.0; // B is all 3's

谢谢!

Answer 1

你复制的方式不对。

thrust::copy(d_data.begin(), d_data.end(), m.d_data.begin() );

应该是:

thrust::copy(m.d_data.begin(), m.d_data.end(), d_data.begin() );