Question

3. Please complete the example given in lecture;
Programs to display pyramid and inverted pyramid using * or # and digits

*
* * *
* * * * *
* * * * * * *
* * * * * * * * *

Press “1” button add 1 into the pyramid.
Press “1” to move number 1 to next cell (if it is the end of the triangle, loopback)
Press “2” to move number 1 to previous cell (if it is the end of the triangle, loopback)

First press
1
* * *
* * * * *
* * * * * * *
* * * * * * * * *
Second press
*
1 * *
* * * * *
* * * * * * *
* * * * * * * * *
Eighth press
*
* * *
* * * 1 *
* * * * * * *
* * * * * * * * *

Please write in cpp

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

#include<iostream>

using namespace std;

//method to print the triangle with given number of rows, one_location is the location of 1

void printTriangle(int rows, int one_location){

                //initial number of columns

                int cols=1;

                //counter to count each cell

                int counter=0;

                //looping through each row

                for(int i=0;i<rows;i++){

                                //looping through each column

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

                                               //updating counter

                                               counter++;

                                               //if counter and one_location are same, printing 1

                                               if(counter==one_location){

                                                               cout<<"1";

                                               }

                                               //else printing a '*'

                                               else{

                                                               cout<<"*";

                                               }

                                              

                                }

                                //line break

                                cout<<endl;

                                //increasing number of columns by 2

                                cols+=2;

                }

}

int main(){

                //number of rows

                int rows=5;

                //total number of cells = rows^2

                int numCells=rows*rows;

                //initial location of 1 (outside)

                int oneLocation=0;

                //to store user input

                int input=0;

                //denoting if the 1 is added or not

                bool one_added=false;

                //looping as long as 3 is not entered (an exit case)

                while(input!=3){

                                //printing triangle

                                printTriangle(rows,oneLocation);

                                //printing menu

                                cout<<endl<<"Press \"1\" button add 1 into the pyramid."<<endl;

                                cout<<"Press \"1\" to move number 1 to next cell."<<endl;

                                cout<<"Press \"2\" to move number 1 to previous cell."<<endl;

                                cout<<"Press \"3\" to exit."<<endl; //for exiting the program

                                cout<<"Choice: ";

                                //getting input

                                cin>>input;

                                cout<<endl; //line break

                                if(input==1){

                                               //if 1 is not added, adding to cell 1

                                               if(!one_added){

                                                               oneLocation=1;

                                                               one_added=true;

                                               }else{

                                                               //otherwise, incrementing oneLocation

                                                               oneLocation++;

                                                               //wrapping around if goes out of range

                                                               if(oneLocation>numCells){

                                                                               oneLocation=1;

                                                               }

                                               }

                                }else if(input==2){

                                               //if 1 is added to the triangle, updating oneLocation to previous cell

                                               if(one_added){

                                                               oneLocation--;

                                                               //wrapping around if necessary

                                                               if(oneLocation<1){

                                                                               oneLocation=numCells;

                                                               }

                                               }else{

                                                               //1 is not added yet

                                                               cout<<"Add 1 first"<<endl;

                                               }

                                              

                                }

                               

                }             

                return 0;

}

/*OUTPUT*/

*

***

*****

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 2

Add 1 first

*

***

*****

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

1

***

*****

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 2

*

***

*****

*******

********1

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 2

*

***

*****

*******

*******1*

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

***

*****

*******

********1

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

1

***

*****

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

1**

*****

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

*1*

*****

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

**1

*****

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

***

1****

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

***

*1***

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

***

**1**

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

***

***1*

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 1

*

***

****1

*******

*********

Press "1" button add 1 into the pyramid.

Press "1" to move number 1 to next cell.

Press "2" to move number 1 to previous cell.

Press "3" to exit.

Choice: 3