In this post, we are going to learn the process of multiplication of two 2D arrays and display the resulting array on screen.
Example:
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Multiplication of Matrices |
Below are a few points to keep in mind before performing Matrix Multiplication:
- Matrix multiplication is only possible when the number of columns of the first matrix should be equal to the number of rows of the second matrix.
- In matrix multiplication, the product of an m x k matrix and k x n matrix is an m x n matrix.
- Matrix multiplication is not commutative in nature, it means the order multiplication of two matrices matters and can change our result.
- Each entry in the resulting matrix is the dot product of row elements of the first matrix with column elements of the second matrix.
Below is C++ Code Implementation:
//Program to for Multiplication of 2D Array (Matrix) #include<iostream> using namespace std; int main(){ int arr1[50][50], arr2[50][50], prod[50][50] = {0}; int row1, col1, row2, col2; //column of first matrix should be equal to row of second matrix do{ cout<<"Enter number of rows and columns for first matrix: "; cin>>row1>>col1; cout<<"Enter number of rows and columns for second matrix: "; cin>>row2>>col2; }while(col1 != row2); //Taking input for first matrix cout<<"Enter the elements of first Array: "<<endl; for(int i = 0; i < row1; i++){ for(int j = 0; j < col1; j++){ cout<<"Enter element for position arr["<<i<<"]["<<j<<"] = "; cin>>arr1[i][j]; } } //Taking input for second matrix cout<<"Enter the elements of second Array: "<<endl; for(int i = 0; i < row2; i++){ for(int j = 0; j < col2; j++){ cout<<"Enter element for position arr["<<i<<"]["<<j<<"] = "; cin>>arr2[i][j]; } } //Multiplication of Matrix cout<<"The Multiplication of two Matrices: "<<endl; for(int i = 0; i < row1; i++){ for(int j = 0; j < col2; j++){ for(int k = 0; k < col1; k++){ prod[i][j] = arr1[i][k] * arr2[k][j]; } } } cout<<"Displaying Product of Two Matrix: "<<endl; for(int i = 0; i < row1; i++){ for(int j = 0; j < col2; j++){ cout<<prod[i][j]<<" "; } cout<<endl; } return 0; }
Enter number of rows and columns for first matrix: 2 3
Enter number of rows and columns for second matrix: 3 2
Enter the elements of first Array:
Enter element for position arr[0][0] = 1
Enter element for position arr[0][1] = 2
Enter element for position arr[0][2] = 3
Enter element for position arr[1][0] = 4
Enter element for position arr[1][1] = 5
Enter element for position arr[1][2] = 6
Enter the elements of second Array:
Enter element for position arr[0][0] = 6
Enter element for position arr[0][1] = 5
Enter element for position arr[1][0] = 4
Enter element for position arr[1][1] = 3
Enter element for position arr[2][0] = 2
Enter element for position arr[2][1] = 1
The Multiplication of two Matrices:
6 3
12 6
In the above code, we have taken the first matrix of size 2 x 3 and the second matrix of size 3 x 2 and the resultant matrix that we get after multiplication is of size 2 x 2 which is satisfying our matrix property.
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