C++
1. write a test program that prompts the user to entrer two 3x3 matrices and displays their sums.

The program to this question as follows:

Program:

//header file iostream

#include<iostream> //including file for use basic function

//using name space

using namespace std;

//main method

int main() //defining main method

{

   int a[3][3]; //defining two dimension array

   int x,y,sum=0; //defining variables

   cout<<"Enter array elements: "<<endl; //message

   for(x=0;x<3;x++) // for row

   {

       for(y=0;y<3;y++) //for column

       {

          cin>>a[x][y]; //input values from user.

       }

   }

   //loop for calculting sum.

   for(x=0;x<3;x++)

   {

       for(y=0;y<3;y++)

       {

       sum=sum+a[x][y];//add all elements

       }

   }

   cout<<"Sum: "<<sum; //print sum.

   return 0;

}

Output:

Enter array elements:  

1

2

3

4

5

6

7

8

9

Sum: 45

Explanation:

In the above C++ programming language code first, a header file is included then the main method is declared, inside a main method 2D array that is "a[][]", and an integer variable is defined that are "i, j, and sum". In the next line for loop is used, this loop is used two times that can be described as follows: