Matrix矩阵类

/Matrix.h//矩阵类定义#ifndef MATRIX_H#define MATRIX_H#include <iostream>#include <string>//using namespace std; 一般头文件中使用完全限定域名字，而不是包含命名空间，防止重复包含头文件时造成的资源浪费class Matrix{//从流中读入矩阵friend std::istream& operator >> (std::istream& is, Matrix A);//输出矩阵friend std::ostream& operator << (std::ostream& os, const Matrix& A);//将矩阵输出到名为str的文件中friend void print_file(const Matrix&A,const char* str);public://定义空矩阵Matrix() {elems = NULL; row = 0; col = 0;};//定义m*n零矩阵Matrix(int m, int n);//定义m*n矩阵，由a初始化Matrix(int m, int n, double *a, int size = 0);//复制构造函数Matrix(const Matrix& B);//从文件str中读取矩阵Matrix(const char* str);~Matrix() {delete[]elems; row = 0; col = 0; };//重载算数操作符Matrix& operator = (Matrix& B);Matrix operator +(const Matrix&B)const;Matrix operator -(const Matrix&B)const;Matrix operator *(const Matrix&B)const;//返回矩阵第i行第j列元素double& operator()(int i,int j)const;double get_row()const {return row;};double get_col()const {return col;};//矩阵转置Matrix& trans()const;protected:private:double* elems;int row, col;};#endif1//Matrix.cpp2//函数实现34#include "Matrix.h"5#include <iostream>6#include <fstream>7#include <sstream>8#include <string>9#include <stdexcept>1011using namespace std;1213//重载下标操作符，返回A[i,j]14double& Matrix::operator()(int i,int j)const15{16if(i<0 || i >= row || j < 0 || j >= col)17throw out_of_range("The suffix is out of range"); 1819return elems[i*col+j];20}2122//从输入流中读入矩阵23istream& operator >>(istream& is, Matrix&A)24{25for(int i = 0; i != A.get_row(); ++i)26for(int j = 0; j != A.get_col(); ++j)27is >> A(i,j);28return is;29}3031//输出矩阵32ostream& operator <<(ostream& os, const Matrix& A) 33{34for(int i = 0; i != A.get_row(); ++i)35 {36for(int j = 0; j != A.get_col(); ++j)37 os << A(i,j) << " ";38 cout <<endl;39 }40 cout << "------------------------" <<endl;4142return os;4344};4546//将矩阵A输出到文件str中47void print_file(const Matrix&A,const char* str)48{49 ofstream outfile("Matrix_out.txt",ios::app);50if(!outfile)51throw domain_error("Cannot open this file.");5253for(int i = 0; i != A.row; ++i)54 {55for(int j = 0; j!= A.col; ++j)56 outfile << A(i,j);57 outfile << endl;58 }59 outfile << "----------------------"<<endl;6061 outfile.clear();62 outfile.close();63}6465//构造m*n零矩阵66Matrix::Matrix(int m, int n):row(m),col(n)67{68if(m <1 || n <1)69throw out_of_range("The row or column number should be larger tha n 0.");70 elems = new double[m*n];71for(int i = 0; i != m*n; ++i)72 elems[i] = 0;73}7475//构造m*n矩阵，从数组a中读入数据存储到矩阵中76Matrix::Matrix(int m, int n,double* a, int size):row(m),col(n)77{78if(m <0 || n<0 || size < m*n)79throw out_of_range("The suffix or size are out of range"); 8081 elems = new double[m*n];82for(int i = 0; i != m*n; ++i)83 elems[i] = a[i];8485};8687//从文件中读入矩阵88Matrix::Matrix(const char* str)89{90//忘了刚开始的行列初始化，导致错误，寻找了半天。

91 row = 0;92 col = 0;9394 ifstream infile(str,ios::in);95if(!infile)96 {97throw domain_error("Cannot find this file.");98 }99100char ch = ' ';101//计算列数102while(infile.get(ch) && ch != '\n')103 {104if(ch == ' ') ++col;105 }106 ++col;107108//计算行数109 infile.clear(); //在这里这个语句不必要110 infile.seekg(0,ios::beg);//千万不能忘了重定位到文件头111while(infile.get(ch))112 {113if(ch == '\n') ++row;114 }115 ++row;116117 infile.clear();//已经读到文件尾时想重新定位到文件头必须有这条语句118 infile.seekg(0,ios::beg);119120 elems = new double[row*col];122while(i != row*col)123 infile >> elems[i++];124125 infile.clear();126 infile.close();127128}129130//矩阵复制构造函数131Matrix::Matrix(const Matrix& B):row(B.row),col(B.col)132{133if((row != B.row) || (col != B.col))134throw invalid_argument("The Matrix should be matched."); 135136 elems = new double[row*col];137for(int i = 0; i != row*col; ++i)138 elems[i] = B.elems[i];139140};141142//重载矩阵赋值操作符143Matrix& Matrix::operator = (Matrix& B)144{145146if((row != B.row) || (col != B.col))147throw invalid_argument("The matrix should be matched."); 148 row = B.row;149 col = B.col;150 elems = new double[row*col];151for(int i = 0; i != row*col; ++i)152 elems[i] = B.elems[i];153154return *this;155};156157//重载矩阵相加操作符158Matrix Matrix::operator+(const Matrix& B)const159{160if((row != B.row) || (col != B.col))161throw invalid_argument("The matrix should be matched"); 162163 Matrix& T = * new Matrix;164 T.row = row;166 T.elems = new double[row*col];167168for(int i = 0; i != row*col; ++i)169 T.elems[i] = elems[i] + B.elems[i];170return T;171172};173174//重载矩阵相减操作符175Matrix Matrix::operator-(const Matrix& B)const176{177if((row != B.row) || (col != B.col))178throw invalid_argument("The matrix should be matched");179180 Matrix& T = * new Matrix;181 T.row = row;182 T.col = col;183 T.elems = new double[row*col];184185for(int i = 0; i != row*col; ++i)186 T.elems[i] = elems[i] - B.elems[i];187return T;188189};190191//重载矩阵相乘操作符192Matrix Matrix::operator *(const Matrix& B)const193{194if( col != B.row)195throw invalid_argument("The matrix should be matched."); 196197 Matrix& T = *new Matrix;198 T.row = row;199 T.col = B.col;200 T.elems = new double[T.row * T.col];201202for(int i = 0; i != T.row; ++i)203for(int j = 0; j != T.col; ++j)204 {205 T.elems[i * T.col + j] = 0;206for(int k = 0; k != col; ++k)207 T.elems[i * T.col + j] += elems[i * col + k] * B.elems[k*B.co l + j];208 }209210return T;211};212213//转置矩阵214Matrix& Matrix::trans()const215{216 Matrix& T = *new Matrix; //new 返回的是指针，需要解引用217 T.row = col;218 T.col = row;219 T.elems = new double[row*col];220for(int i = 0; i != T.row; ++i)221for(int j = 0; j != T.col; ++j)222 T.elems[i*T.col + j] = elems[j*col + i];223return T;224}1//Mainfun.cpp2//测试编写的矩阵类3#include "Matrix.h"4#include <iostream>5#include <string>6#include <fstream>7#include <cstdlib>8#include <stdexcept>910using namespace std;1112int main()13{14double d[12] = {1,2,3,4,5,6,7,8,1,2,3,4};15double d2[12] = {1,2,3,4,1,2,3,4,5,6,7,8};16 Matrix A(3,4,d,12);17 Matrix B(3,4,d2,12);18 Matrix C= B.trans();1920 cout << "A = \n" << A << "B = \n" << B << "C = \n" <<C<<endl;21 cout << "A + B \n" << A + B << "B*C \n" << B*C <<endl;2223//将矩阵输出到文件Matrix_out.txt中24 print_file(A,"Matrix_out.txt");2526//从文件"Matrix_in.txt"中读取矩阵27 Matrix D("Matrix_in.txt");28 cout << D <<endl;2930//异常处理的写起来太繁琐了，只示例一个，其他省略了。