Question

假设我们想从给定矩阵中减去一些值。怎么可能/我应该重载该运算符。

的main.cpp

Matrix<double> m(10, 5);

auto r = 1.0 - m; //error: return type specified for 'operator double'

matrix.hpp

template <typename T>
class Matrix {
public:
  Matrix operator double(T val) {
    Matrix tmp(rows, cols);

    for (unsigned int i = 0; i < rows; i++)
      for (unsigned int j = 0; j < cols; j++) {
        const unsigned int idx = VecToIdx({i, j});
        tmp[idx] = val - this[idx];
      }

    return tmp;
  }
}

Answer 1

您的代码正在尝试从Matrix中减去double，但您的问题要求从double中减去Matrix。这是两个不同的操作。你真的想做什么？

在后一种情况下，您需要重载减法运算符，而不是转换运算符，例如：

template <typename T>
class Matrix {
public:
    Matrix operator- (T val) {
        Matrix tmp(rows, cols);
        for (unsigned int i = 0; i < rows; i++)
            for (unsigned int j = 0; j < cols; j++) {
                const unsigned int idx = VecToIdx({i, j});
                tmp[idx] = (*this)[idx] - val;
            }
        return tmp;
    }
};

Matrix<double> m(10, 5);

auto r = m - 1.0;

C ++运算符重载<double> - <matrix>

1 个答案: