Work with matrices

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main(){

  int mat1[2][2], mat2[3][3];

// Task 1 and Task 2
  cout << "Input first matrix:" << endl;
  for (int i = 0; i < 2; i++){
    for (int j = 0; j < 2; j++){
      cin >> mat1[i][j];
    }
  }

  cout << endl << "Input second matrix:" << endl;
  for (int i = 0; i < 3; i++){
    for (int j = 0; j < 3; j++){
      cin >> mat2[i][j];
    }
  }

  // Task 3

  cout << endl << "First matrix:" << endl;
  for (int i = 0; i < 2; i++){
    for (int j = 0; j < 2; j++){
      cout << mat1[i][j] << " ";
    }
    cout << endl;
  }

  cout << endl << "Second matrix:" << endl;
  for (int i = 0; i < 3; i++){
    for (int j = 0; j < 3; j++){
      cout << mat2[i][j] << " ";
    }
    cout << endl;
  }

  // Task 4 and input for Task 5

  cout << "Input size of matrices: ";
  vector <vector <int>> matrix1, matrix2, matrix_sum, matrix_sub;
  int size, num; cin >> size;

  cout << endl << "Input first matrix:" << endl;
  for (int i = 0; i < size; i++){
    vector <int> temp;
    for (int j = 0; j < size; j++){
      cin >> num;
      temp.push_back(num);
    }
    matrix1.push_back(temp);
  }

  cout << endl << "Input second matrix:" << endl;
  for (int i = 0; i < size; i++){
    vector <int> temp;
    for (int j = 0; j < size; j++){
      cin >> num;
      temp.push_back(num);
    }
    matrix2.push_back(temp);
  }

  for (int i = 0; i < size; i++){
    vector <int> temp;
    for (int j = 0; j < size; j++){
      temp.push_back(matrix1[i][j] + matrix2[i][j]);
    }
    matrix_sum.push_back(temp);
  }

  cout << endl << "Sum matrix:" << endl;
  for (int i = 0; i < size; i++){
    for (int j = 0; j < size; j++){
      cout << matrix_sum[i][j] << " ";
    }
    cout << endl;
  }

  // Task 5

  for (int i = 0; i < size; i++){
    vector <int> temp;
    for (int j = 0; j < size; j++){
      temp.push_back(matrix1[i][j] - matrix2[i][j]);
    }
    matrix_sub.push_back(temp);
  }

  cout << endl << "Sub matrix:" << endl;
  for (int i = 0; i < size; i++){
    for (int j = 0; j < size; j++){
      cout << matrix_sub[i][j] << " ";
    }
    cout << endl;
  }

  return 0;
}