mfc函数声明与已声明不兼容

Question

mfc中在view.cpp中声明一个函数，再在view.中添加声明，.cpp中报错声明不兼容

//view.cpp中：
void C实验二View::matrix3x3multiply(Matrix3x3 m1, Matrix3x3 m2)
{
    int row, col;
    Matrix3x3 mattemp;
    for (row = 0; row < 3; row++)
        for (col = 0; col < 3; col++)
            mattemp[row][col] = m1[row][0] * m2[0][col] + m1[row][1] * m2[1][col] + m1[row][2] * m2[2][col];
    for (row = 0; row < 3; row++)
        for (col = 0; col < 3; col++)
            m2[row][col] = mattemp[row][col];
}
void C实验二View::Matrix3x3setidentity(Matrix3x3 matident3x3)
{
    int row, col;
    for (row = 0; row < 3; row++)
        for (col = 0; col < 3; col++)
            matident3x3[row][col] = (row == col);
}

//view中
    virtual void C实验二View::matrix3x3multiply(Matrix3x3 m1, Matrix3x3 m2);
    virtual void C实验二View::Matrix3x3setidentity(Matrix3x3 matident3x3);

查了一下有人说是因为头文件反复包含，我看了一下，我好像没有反复包含
cpp中包含.h都只有一个

求解答 很疑惑

Answer 1

view.h中

virtual void matrix3x3multiply(Matrix3x3 m1, Matrix3x3 m2);
virtual void Matrix3x3setidentity(Matrix3x3 matident3x3);