Question

Write a program in C++ that defines a two-dimensional array of integers of size 4x4. The program will fill the array with values using the equation array_name[j][i] = i+j+2 (j = row index, i = column index). Define a one-dimensional array of size 4. The one-dimensional array should be filled with the values along the main diagonal of the two-dimensional array.

Answer 1

I've written the code in c++ as per requirements of the question. I've also commented it for easy understanding.

Code

#include<iostream>

using namespace std;

int main(){

    //declaring array

    int array_name[4][4];

    //for each row

    for(int row=0;row<4;row++){

        //for each column

        for(int col=0;col<4;col++){

            array_name[row][col]=row+col+2; //set array value as required

            //row and col in c++ start at 0

        }

    }

    //printing the matrix

    cout<<"Array_Names\n";

    for(int row=0;row<4;row++){

        for(int col=0;col<4;col++){

            cout<<array_name[row][col]<<" ";

        }

        cout<<endl;

    }

    //diagonal array to hold elements of main diagonal

    int diagonal[4];

    int index=0;

    int row=0,col=0;

    //while row and column are within limits

    while(row<4 && col<4){

        //set values of diagonal

        diagonal[index]=array_name[row][col];

        //increment index

        index++;

        //row and column both increase since diagonal move require increased row and column

        row++;

        col++;

    }

    //printing the diagonal array

    cout<<"Diagonal\n";

    for(int index=0;index<4;index++)

        cout<<diagonal[index]<<" ";

}

Output

For Indentation Purpose