C++ 报错相关

Expression must have class type

    T operator[](size_t idx) const noexcept {
        assert(idx < data_.size()); // 此处报错
        return data_[idx];
    }

    T& operator[](size_t idx) noexcept {
        assert(idx < data_.size()); // 此处报错
        return data_[idx];
    }

private:
    T* data_{ nullptr };
    size_t rows_{0};
    size_t cols_{0};

上述代码中，编译时出现错误 expression must have class type but it has type "T *const"

只需把 data_.size() 改成 data_->size() 可解决

参考链接（需要魔法）：https://stackoverflow.com/questions/6547602/expression-must-have-class-type