How to print arrays’s mirror image of 2D array (3X3) in C++

By Yash Shakya

In this tutorial, we are going to write a program to enter integers in a 2D array (3X3) and display the array’s mirror image in C++. This program is a very important program as an application of array concept.

It is often asked in interviews and many written examinations and you are supposed to answer the same. If you are searching for the solution of similar program then you are at the right place. I am providing you a very detailed and easy method to do this.

Display or print mirror image of 2D array (3X3) in C++

The mirror image of a 2D array of size 3X3 depends on the position of mirror. In that case, four situations arise in front of us as mirror position on

1. Top
2. Bottom
3. Left side
4. Right side of array

In case 1 and 2 the mirror images are like this.

Similarly in case 3 and 4 the mirror images are like this.

So now we can conclude for the images that the top and down as well as left and right mirror images will be the same. So there arise only two cases-

1. Top and bottom mirror image.
2. Left and right mirror image.

Also read

Remove or eliminate extra spaces from a string in C++

Insert an element in an array in C++

Array’s mirror image for top and bottom mirror position

Methodology

The logic behind the code is entering the array elements by user, then it simply enters the image elements by just exchanging the first row with the third row and vice versa. The second row remains as it is. In the code, we exchange the original array “array” with the image array “arrayimg” by following line of code.

for(int i=0;i<3;i++){                       //prepare array's image data
    for(int j=0;j<3;j++){
        arrayimg[i][j]=array[2-i][j];        // logic for array's image
    }
}

Program code

This code is tested and its working fine in CodeBlocks v 16.01.

#include <iostream>
#include<string.h>

using namespace std;

int main()
{
    int array[3][3];                            // original array
    int arrayimg[3][3];                         // image array
    cout<<"Enter 9 array elements "<<endl;
    
    for(int i=0;i<3;i++){                       // enter original array data 
        for(int j=0;j<3;j++)
            cin>>array[i][j];
    }
    
    for(int i=0;i<3;i++){                       //prepare array's image data
        for(int j=0;j<3;j++){
            arrayimg[i][j]=array[2-i][j];        // logic for array's image
        }
    }
    
    cout<<"Original array elements-"<<endl;     
    for(int i=0;i<3;i++){
        for(int j=0;j<3;j++)
            cout<<array[i][j]<<"\t";            //print original array
        cout<<endl;
    }
    
    cout<<"Array's image for mirror at above and bottom position of array-"<<endl;
    for(int i=0;i<3;i++){
        for(int j=0;j<3;j++)
            cout<<arrayimg[i][j]<<"\t";         //print image elements
        cout<<endl;
    }
    return 0;
}

Output example

Enter 9 array elements
45
14
65
32
41
28
71
69
26
Original array elements-
45      14      65
32      41      28
71      69      26
Array's image for mirror at above and bottom position of array-
71      69      26
32      41      28
45      14      65

Array’s mirror image for left and right mirror position

Methodology

The logic for this program will be same as we have done above. Just a small difference i.e. instead of exchanging rows we will replace first column with the third and again the second i.e. middle column will remain as it is.

This is achieved by following code lines

for(int i=0;i<3;i++){                       //prepare array's image data
    for(int j=0;j<3;j++){
        arrayimg[i][j]=array[i][2-j];        // logic for array's image
    }
}

Program code

#include <iostream>
#include<string.h>

using namespace std;

int main()
{
    int array[3][3];                            // original array
    int arrayimg[3][3];                         // image array
    cout<<"Enter 9 array elements "<<endl;

    for(int i=0;i<3;i++){                       // enter original array data
        for(int j=0;j<3;j++)
            cin>>array[i][j];
    }

    for(int i=0;i<3;i++){                       //prepare array's image data
        for(int j=0;j<3;j++){
            arrayimg[i][j]=array[i][2-j];        // logic for array's image
        }
    }

    cout<<"Original array elements-"<<endl;
    for(int i=0;i<3;i++){
        for(int j=0;j<3;j++)
            cout<<array[i][j]<<"\t";            //print original array
        cout<<endl;
    }

    cout<<"Array's image for mirror at left and right position of array-"<<endl;
    for(int i=0;i<3;i++){
        for(int j=0;j<3;j++)
            cout<<arrayimg[i][j]<<"\t";         //print image elements
        cout<<endl;
    }
    return 0;
}

Example output

Enter 9 array elements
14
56
29
4
31
47
68
21
16
Original array elements-
14      56      29
4       31      47
68      21      16
Array's image for mirror at left and right position of mirror-
29      56      14
47      31      4
16      21      68

Hope you are now able to understand the logic behind these programs.