#ifndef CMATRIX_H #define CMATRIX_H #include <iostream> using namespace std; class CMatrix { public: //函数的构建 CMatrix(); CMatrix(int nRow, int nCol, double* pData = NULL); CMatrix(const CMatrix& m); CMatrix(const char* strPath); ~CMatrix(); //函数的创建删除和设置 bool Create(int nRow, int nCol, double* pData = NULL); void Set(int nRow, int nCol, double dVale); void Release(); //友元函数,访问私有变量 friend istream& operator>>(istream& is, CMatrix& m); friend ostream& operator<<(ostream& os, const CMatrix& m); //操作符重载 CMatrix& operator =(const CMatrix& m); CMatrix& operator +=(const CMatrix& m); double& operator[](int nIndex); double& operator()(int nRow, int nCol); bool operator ==(const CMatrix& m); bool operator !=(const CMatrix& m); operator double(); //私有变量 private: int m_nRow; int m_nCol; double* m_pData; }; CMatrix operator+(const CMatrix& m1, const CMatrix& m2); //内联函数 inline void CMatrix::Set(int nRow, int nCol, double dVal) { m_pData[nRow * m_nCol + nCol] = dVal; } #endif
(1)构造器。 本次实验提供四个构造器,下面四个构造器分别为无参构造器,有参构造器,已经复制已有的类创建新的类,通过文件读入构造。
CMatrix::CMatrix() :m_nRow(0), m_nCol(0), m_pData(0) { }
CMatrix::CMatrix(int nRow, int nCol, double* pData) : m_pData(0) { Create(nRow, nCol, pData); }
CMatrix::CMatrix(const CMatrix& m) : m_pData(0) { *this = m; }
CMatrix::CMatrix(const char* strPath) { m_pData = 0; m_nRow = m_nCol = 0; ifstream cin(strPath); cin >> *this; }
(2)下面为对象的创建,删除和析构函数。析构函数为当对象结束其生命周期,系统自动执行析构函数。例如在建立对象时用new开辟了一片内存空间,delete会自动调用析构函数后释放内存
bool CMatrix::Create(int nRow, int nCol, double* pData) { Release(); m_pData = new double[nRow * nCol]; m_nRow = nRow; m_nCol = nCol; if (pData != NULL) { memcpy(m_pData, pData, nRow * nCol * sizeof(double)); return true; } else { return false; } }
void CMatrix::Release() { if (m_pData!=NULL) { delete []m_pData; m_pData = NULL; } m_nRow = m_nCol = 0; }
CMatrix::~CMatrix() { Release(); }
(3)运算符重载:下面分别对‘=’,‘+=’,‘+’,‘==’,‘!=’进行重载
CMatrix& CMatrix::operator=(const CMatrix& m) { if (this != &m) { Create(m.m_nRow, m.m_nCol, m.m_pData); } return *this; }
CMatrix& CMatrix::operator+=(const CMatrix& m) { assert(m_nRow == m.m_nRow && m_nCol == m.m_nCol); for (int i = 0; i < m_nRow * m_nCol; i++) { m_pData[i] += m.m_pData[i]; } return *this; }
CMatrix operator+(const CMatrix& m1, const CMatrix& m2) { CMatrix m3(m1); m3 += m2; return m3; }
bool CMatrix::operator == (const CMatrix& m) { if (!(m_nRow == m.m_nRow && m_nCol == m.m_nCol)) { return false; } for (int i = 0; i < m_nRow * m_nCol; i++) { if (m_pData[i] != m.m_pData[i]) { return false; } } return true; }
bool CMatrix::operator !=(const CMatrix& m) { return !((*this) == m); }
(4)操作符重载:下面分别对‘[]’,‘()’,‘<<’,‘>>'进行重载
double& CMatrix::operator[](int nIndex) { assert(nIndex < m_nRow* m_nCol); return m_pData[nIndex]; }
double& CMatrix::operator()(int nRow, int nCol) { assert(nRow * m_nCol + nCol < m_nRow* m_nCol); return m_pData[nRow * m_nCol + nCol]; }
istream& operator>>(istream& is, CMatrix& m) { is >> m.m_nRow >> m.m_nCol; m.Create(m.m_nRow, m.m_nCol,m.m_pData); for (int i = 0; i < m.m_nRow * m.m_nCol; i++) { is >> m.m_pData[i]; } return is; }
ostream& operator<<(ostream& os, const CMatrix& m) { os << m.m_nRow << " " << m.m_nCol << endl; double* pData = m.m_pData; for (int i = 0; i < m.m_nRow; i++) { for (int j = 0; j < m.m_nCol; j++) { os << *pData++ << " "; } os << endl; } return os; }
(5)数据类型转换,将创建的对象强制转换成double类
CMatrix::operator double() { double dS = 0; for (int i = 0; i < m_nRow * m_nCol; i++) { dS += m_pData[i]; } return dS; }
#include <iostream> #include <stdio.h> #include "CMatrix.h" using namespace std; int main(int argc, char** argv) { double pData[10] = { 2,3,4,5 }; CMatrix m1,m2(2, 5, pData), m3("d:\\1.txt"), m4(m2); cout << "输入矩阵行,列和对于数量的数值:" << endl; cin >> m1; m2.Set(1, 3, 10); cout << "m1=" << m1 << "\nm2=" << m2 << "\nm3=" << m3 << "\nm4=" << m4; m4 = m3; m4[2] = m4 + 1; if (m4 == m3) { cout << "Error !" << endl; } m4 += m3; cout << "\nm4=" << m4 << endl; cout << "sum of m4 = " << (double)m4 << endl; return 0; }
本次实验涉及到类的创建,删除,已经运算符的重载,对类的强制类型转换等等。还有析构函数的使用。本次实验编写明白很多项目构建的问题,其中对于内敛函数,无参函数让系统更快运行也有了深刻影响。对于各类重载方法有了大致的了解。