Question

Using C++

Write a function that given two dynamical arrays (A and B) of doubles of a given size N, will return a N by N dynamical array C such that C[i][j]=A[i]*B[j]. e.g. A={1,2,3}, B={10,20,30}, will result in C={{10,20,30},{20,40,60}, {30, 60, 90}}

double** outerProd(double *A, double *B, int size);

Answer 1

//C++ code

#include<iostream>
using namespace std;
//function prototype
double** outerProd(double *A, double *B, int size);
//main function
int main()
{
   int size = 3;
   double *A = new double[size] { 1, 2, 3 };
   double *B = new double[size]{ 10,20,30 };
   //call the function
  
   double **c = outerProd(A, B, size);

   //print the array
   cout << "{"<<endl;
   for (int i = 0; i < size; i++)
   {
       cout << "{";
       for (int j = 0; j < size; j++)
       {
           cout << c[i][j] << ",";
       }
       cout << "}" << endl;
   }
   cout << "}" << endl;
   //to hold the output screen
   system("pause");
   return 0;
}

//function definition
double** outerProd(double *A, double *B, int size)
{
   double **c ;
   c = new double*[size];
   for (int i = 0; i < size; i++)
   {
       c[i] = new double[size];
       for (int j = 0; j < size; j++)
       {
           c[i][j] = A[i]*B[j];
       }
   }
   return c;
}

//output

//If you need any help regarding this solution ............ please leave a comment .......... thanks