Question

Question 1:

Fix the 2D dynamic array initialization in following code

#include <iostream>

using namespace std;

int main(){
  
int rows = 5;
int cols = 5;
int x;
  
int** arr = new int[rows][cols]
  
cin >> x;
arr[x][x] = x;
cout << "arr[x][x] = " << arr[x][x];
  
return 0;
}

Question 2:

Fix the code to initialize the 2D array elements to x

#include <iostream>

using namespace std;

int main(){
  
int rows;
int cols;
int x;
  
cin >> rows;
cin >> cols;
cin >> x;
  
int** arr = new int*[rows];
for(int i = 0; i < rows; ++i)
arr[i] = new int[cols];
  
// initialization, your code goes here

  
  
for(int i = 0; i < 3; i++){ // prints some values in the array
for(int j = 0; j < 3; j++)
cout << arr[i][j];
cout <<"\n";
}
  
return 0;
}

Answer 1

CodeToCopy:

Question 1:

2darray_init.cpp

#include <iostream>

using namespace std;

int main(){

    int rows = 5;

    int cols = 5;

    int x;

    /* allocating memory for rows */

    int** arr = new int*[rows];

    /* allocating memory for columns */

    for (int i = 0; i < rows; ++i ) {

        arr[i] = new int[cols];

    }

    /* taking x from user */

    cin >> x;

   

    /* place x at x'th row, x'th column */

    arr[x][x] = x;

   

    /* printing x'th row, x'th column value */

    cout << "arr[x][x] = " << arr[x][x] << endl;

    return 0;

}

Question 2:

2darray_init2.cpp

#include <iostream>

using namespace std;

int main(){

    int rows;

    int cols;

    int x;

     

    cin >> rows;

    cin >> cols;

    cin >> x;

     

    int** arr = new int*[rows];

    for(int i = 0; i < rows; ++i) {

        arr[i] = new int[cols];

       

        /* assigning x value to 2d array elements */

        for (int j = 0; j < cols; ++j) {

            arr[i][j] = x;

        }

    }

     

    for(int i = 0; i < 3; i++){ // prints some values in the array

        for(int j = 0; j < 3; j++)

            cout << arr[i][j] << " ";

        cout <<"\n";

    }

     

    return 0;

}

OutputScreenshot: