Question

You will write a program in C that multiplies a matrix by a vector, using MATLAB to check the results. Create a program in MATLAB to solve the Topic 5 "File I/O" assignment. Use any built-in MATLAB functions of your choice. Some might require you to change your input files slightly; if so, document what you did and explain why. Compare and contrast the C and MATLAB versions of your code.

Answer 1

C++ Code :

#include <stdio.h>
#include <stdlib.h>

int main()
{
   int i,j,r,c,n;
   r=2,c=4,n=4;
   int mat[2][4] = {5,2,3,1 ,7,6,3,8};      
   int vec[4]={1,9,8,3};
   printf("Matrix :\n");
   for(i=0;i<r;i++)
   {
  
       for(j=0;j<c;j++)
       printf("%d ",mat[i][j]);
       printf("\n");
   }
   printf("Vector :\n");
   for(i=0;i<n;i++)
   {
       printf("%d\n",vec[i]);
   }
  
   //since after multiplication final result will be
   //column vector of 2 elements
   int final[2][1];
   int sum=0;
   //calculating the matrix multiplication
   for(i =0;i<r;i++)
   {
       sum=0;
       for(j=0;j<c;j++)
       {
           sum = sum + mat[i][j]*vec[j];
       }
       final[i][0] = sum;
   }
  

  
   printf("Result after multiplication is :\n");
   for(i=0;i<r;i++)
   printf("%d\n",final[i][0]);
   return 0;
}

Matlab Code:

mat = [5 2 3 1;7 6 3 8];

vec = [1;9;8;3];

mat*vec

Output SS:

C++

Matlab: