Question

To understand the value of counting loops, write a program in C++ that implements matrix multiplication using counting loop constructs. Let the user input the size/dimensions of the matrix. Then write the same program using only logical loops—for example, while loops.

Answer 1

#include <iostream>
using namespace std;
int main()
{
//variable declaration
int a[10][10], b[10][10], c[10][10], row1, col1, row2, col2, i, j, k;
  
//get input from the user
cout<<"Enter rows and columns for first matrix: ";
cin>>row1>>col1;
cout<<"Enter rows and columns for second matrix: ";
cin>>row2>>col2;

//check if multiplication is possible or not
if(col1!=row2)
{
cout<<"Matrices multiplication not possible.";
return 0;
}

//get the elements of first matrix
cout<<endl<<"Enter elements of first matrix:"<< endl;
for(i = 0; i < row1; ++i)
{
for(j = 0; j < col1; ++j)
{
cin >> a[i][j];
}
}

//get the elements of second matrix
cout<<endl<<"Enter elements of second matrix:"<< endl;
for(i = 0; i < row2; ++i)
{
for(j = 0; j < col2; ++j)
{
cin >> b[i][j];
}
}

//multiply the matrix and initialize in the third matrix
for(i = 0; i < row1; ++i)
{
for(j = 0; j < col2; ++j)
{
c[i][j] = 0;
for(k = 0; k < col1; ++k)
{
c[i][j] += a[i][k] * b[k][j];
}
}
}
  
//display the resultant matrix
cout<<endl<<"The resultant matrix is: "<<endl;
for(i = 0; i < row1; ++i)
{
for(j = 0; j < col2; ++j)
{
cout<<c[i][j]<<" ";
}
cout<<endl;
}
return 0;
}

OUTPUT: