#include <iostream>  using namespace std;     void MatrixMultiplication(double *m1,double *m2,double *m3,int m,int n,int k)  {      for(int i=0;i<m;i++)      {          for(int j=0;j<k;j++)          {              double sum = 0.0;              for(int jj=0;jj<n;jj++)              {                  sum += *(m1+i*n+jj)*(*(m2+jj*k+j));              }              *(m3+i*k+j) = sum;          }      }  }     int main(int argc, char* argv[])  {      int m = 1 , n = 3 , k = 3;      double *m1,*m2,*m3;      m1 = new double[m*n];      m2 = new double[n*k];      m3 = new double[m*k];         //[50   50  1]      *(m1+n*0+0) = 50;      *(m1+n*0+1) = 50;      *(m1+n*0+2) = 1;         //[1    0   0]      //[0    1   0]      //[200, 200,1]      *(m2+k*0+0) = 1;      *(m2+k*0+1) = 0;      *(m2+k*0+2) = 0;      *(m2+k*1+0) = 0;      *(m2+k*1+1) = 1;      *(m2+k*1+2) = 0;      *(m2+k*2+0) = 200;      *(m2+k*2+1) = 200;      *(m2+k*2+2) = 1;         MatrixMultiplication(m1,m2,m3,m,n,k);         cout<<"["<<*(m3+k*0+0)<<" ";      cout<<*(m3+k*0+1)<<" ";      cout<<*(m3+k*0+2)<<"]"<<endl;         delete[] m1;      delete[] m2;      delete[] m3;      return 0;  }