C++-重载运算符-矩阵

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<string>
 4 #include<cstring>
 5 #include<cmath>
 6 using namespace std;
 7 class Matrix
 8 {
 9 private:
10     int s;
11     int arr[110][110];
12 public:
13     Matrix(int);
14     Matrix operator+(Matrix &it);
15     Matrix operator-(Matrix &it);
16     Matrix operator*(Matrix &it);
17     friend istream & operator>>(istream &is, Matrix &it);
18     friend ostream & operator<<(ostream &os,const Matrix &it);
19 };
20 Matrix::Matrix(int n=0)
21 {
22     s = n;
23 }
24 Matrix Matrix::operator+(Matrix &it)
25 {
26     Matrix ans(s);
27     for (int i = 1; i <= it.s; i++)
28         for (int j = 1; j <= it.s; j++)
29             ans.arr[i][j] = arr[i][j] + it.arr[i][j];
30     return ans;
31 }
32 Matrix Matrix::operator-(Matrix &it)
33 {
34     Matrix ans(s);
35     for (int i = 1; i <= it.s; i++)
36         for (int j = 1; j <= it.s; j++)
37             ans.arr[i][j] = arr[i][j] - it.arr[i][j];
38     return ans;
39 }
40 Matrix Matrix::operator*(Matrix &it)
41 {
42     Matrix ans(s);
43     for (int i = 1; i <= it.s; i++)
44         for (int j = 1; j <= it.s; j++)
45         {
46             ans.arr[i][j] = 0;
47             for (int k = 1; k <= it.s; k++)
48                 ans.arr[i][j] += arr[i][k] * it.arr[k][j];
49         }
50     return ans;
51 }
52 istream & operator>>(istream &is, Matrix &it)
53 {
54     for (int i = 1; i <= it.s; i++)
55         for (int j = 1; j <= it.s; j++)
56             is >> it.arr[i][j];
57     return is;
58 }
59 ostream & operator<<(ostream &os,const Matrix &it)
60 {
61     for (int i = 1; i <= it.s; i++)
62     {
63         for (int j = 1; j <= it.s; j++)
64             os << it.arr[i][j] << " ";
65         cout << endl;
66     }
67     return os;
68 }
69 int main()
70 {
71     int n; cin >> n;
72     Matrix a(n), b(n);
73     cin >> a >> b;
74     cout << a*b;
75     system("pause");
76     return 0;
77 }

重复造了个矩阵加减乘的轮子，真是累