MatrixChainMult.cpp

main.cc

#include <iostream>
#include <vector>
#include <array>
#include <algorithm>
using namespace std;

template <int T>
void multMatrix(array<array<int, T>, T> a, array<array<int, T>, T> b,
                array<array<int, T>, T> &res) {
  int i, j, k;
  for (i = 0; i < T; ++i) {
    for (j = 0; j < T; ++j) {
      res[i][j] = 0;
    }
  }

  for (i = 0; i < T; ++i) {
    for (j = 0; j < T; ++j) {
      for (k = 0; k < T; ++k) {
        res[i][j] += a[i][k] * b[k][j];
      }
    }
  }
}

int main() {
  const int z = 3;
  int n, i, j;
  cout << "Enter number of 3x3 matrices: ";
  cin >> n;

  vector<array<array<int, z>, z> *> inp;
  array<array<int, z>, z> mult;
  for (int x = 0; x < n; x++) {
    array<array<int, z>, z> *temp = new array<array<int, z>, z>;
    cout << endl << "Enter elements of matrix " << x + 1 << ":" << endl;
    for (i = 0; i < z; ++i) {
      for (j = 0; j < z; ++j) {
        cout << "Enter element (" << i << ", " << j << "): ";
        cin >> (*temp)[i][j];
      }
    }
    inp.push_back(temp);
  }
  mult = *inp[0];

  for (int x = 1; x < n; x++) {
    multMatrix(mult, *inp[x], mult);
  }
  // output
  cout << endl << "Output Matrix: " << endl;
  for (i = 0; i < z; ++i) {
    for (j = 0; j < z; ++j)
      cout << " " << mult[i][j];
    cout << endl;
  }

  for (int x = 1; x < n; x++)
    delete inp[x];

  return 0;
}