习题10.4：有两个矩阵A和B，均为2行3列。求两个矩阵之和。重载运算符“+”，使之能用于矩阵相加。重载运算符“＜＜”和“＞＞”，使之能用于矩阵输入输出。

个人答案：

#include 
#include 
using namespace std;
class Array
{
public:
    Array();
    friend Array operator+(Array a1, Array a2);
    //重载运算符输入输出
    friend istream& operator>>(istream&, Array&);
    friend ostream& operator<<(ostream&, Array&);
private:
    int arr[2][3];
};

//构造矩阵
Array::Array()
{
    int i, j;
    for (i = 0; i < 2; i++)
        for (j = 0; j < 3; arr[i][j++] = 0);
}

//计算式
Array operator+(Array a1, Array a2)
{
    Array a3;
    for (int i = 0; i < 2; i++)
        for (int j = 0; j < 3; j++)
            a3.arr[i][j] = a1.arr[i][j] + a2.arr[i][j];
    return a3;
}

//输入
istream& operator>>(istream& input, Array& a)
{
    int i, j;
    cout << "请输入矩阵: ";
    for (i = 0; i < 2; i++)
        for (j = 0; j < 3; j++)
            input >> a.arr[i][j];
    return input;
}

//输出
ostream& operator<<(ostream& output, Array& a)
{
    int i, j;
    for (i = 0; i < 2; output << endl, i++)
        for (j = 0; j < 3; output << setw(4) << a.arr[i][j], j++);
    return output;
}
int main()
{
    Array a, b, c;
    cin >> a;
    cin >> b;
    c = a + b;
    cout << c;
    system("pause");
    return 0;
}

结果：