#pragma once class GModel; class GModelIndex { friend class GModel; public: GModelIndex() { } bool is_valid() const { return m_row != -1 && m_column != -1; } int row() const { return m_row; } int column() const { return m_column; } void* internal_data() const { return m_internal_data; } bool operator==(const GModelIndex& other) const { return m_row == other.m_row && m_column == other.m_column; } private: GModelIndex(const GModel& model, int row, int column, void* internal_data) : m_model(&model) , m_row(row) , m_column(column) , m_internal_data(internal_data) { } const GModel* m_model { nullptr }; int m_row { -1 }; int m_column { -1 }; void* m_internal_data { nullptr }; };