16.1

#include <iostream>using namespace std;class Matrix{public:    Matrix();    friend Matrix operator+(Matrix &,Matrix &);    friend ostream& operator<<(ostream&,Matrix&);    friend istream& operator>>(istream&,Matrix&);private:    int mat[2][3];};//主函数已给定如下，提交时不需要包含，会自动添加到程序尾部/* C++代码 */Matrix::Matrix(){}Matrix::Matrix operator+(Matrix &c1,Matrix &c2){    Matrix c;    for(int j=0;j<2;j++)    for(int i=0;i<3;i++)    {        c.mat[j][i]=c1.mat[j][i]+c2.mat[j][i];    }    return c;}ostream& operator<<(ostream &output,Matrix &c){    for(int j=0;j<2;j++)    {        for(int i=0;i<2;i++)    {        output<<c.mat[j][i]<<" ";    }    output<<c.mat[j][2]<<endl;    }    return output;}istream& operator>>(istream & input,Matrix & c){    for(int j=0;j<2;j++)     for(int k=0;k<3;k++)     {         input>>c.mat[j][k];     }    return input;}int main(){    Matrix a,b,c;    cin>>a;    cin>>b;    c=a+b;    cout<<c<<endl;    return 0;}