c++ 2 dimentional array- airplane seating

[YingKang]

After user choose ticket type(first class, business, or economy) and desired seat, for example row 2 A, the program will output the form:
A B C D E F
row 1 * * * * * *
row 2 X * * * * * // now user chooses row 2 A
... * * * * * *
row 13 * * * * * *

* indicates the seat is available, X indicates the seat is occupied.
my problem is after the program works the first time, then the user wants to do it again( which I use a while loop) , for example , choose row 1 B, the form will show X at row 1 B, but not the row 2 A ( which the first time the user chose) any more.

A B C D E F
row 1 * X * * * *//user this time chooses row 1 B
row 2 * * * * * *//row 2 A that user has chosen isn't showing now
... * * * * * *
row 13 * * * * * *

Can anyone give me some suggestion to fix the problem? Thank you very much.

#include<iostream>
#include<cctype>
#include<iomanip>

using namespace std;

void getData(char& ticketType, int& row, 
             char& column);
void printForm(char form[][6], int row, char column);

int main()
{
    char ch, ticketType, column;
    int row;
    char form[13][6];
    
    cout << "This program assigns seats for a plane.\n"
         << "Do you want to start now? Y/y for yes, N/n for no." << endl;
    cin >> ch;
    
    ch = static_cast<char>(toupper(ch));
    while(ch == 'Y')     
    { 
   
        getData(ticketType, row, column);
        printForm(form, row, column);
    
        cout << "This program assigns seats for a plane.\n"
             << "Do you want to start now? Y/y for yes, N/n for no." << endl;
        cin >> ch;
        ch = static_cast<char>(toupper(ch));
        if(ch == 'N')
          return 0;     
    }// end while   
    system("PAUSE");
    return 0;
}

void getData(char& ticketType, int& row, char& column)
{   
                             
    cout << "The airplane has 13 rows, with  six seats in each row. " << endl;
           
    cout << "Enter ticket type,\n"
         << "F for first class, \n"
         << "B for business class,\n"
         << "E for economy class:" << endl;
    cin >> ticketType;
    ticketType = static_cast<char>(toupper(ticketType));
    while(ticketType != 'F' && ticketType != 'B' && ticketType != 'E')
    {
        cout << "Invalid ticket type." << endl;
        cout << "Enter ticket type,\n"
             << "F/f for first class, \n"
             << "B/b for business class,\n"
             << "E/e for economy class:" << endl;
        cin >> ticketType;
        ticketType = static_cast<char>(toupper(ticketType));
     }      
    switch(ticketType)
    {
           case 'F':
                cout <<  "Row 1 and 2 are first class,\n" ;
                break;
           case 'B':
                cout <<  "row 3 throuh 7 are business class,\n";
                break;
           case 'E':
                cout <<  "row 8 through 13 are economy class." << endl; 
                break;
    }// end switch
                
    cout << "Enter the row number you want to sit: " << endl ;
    cin >> row;  
    
    cout << "Enter the seat number (from A to F). " << endl;
    cin >> column;
    column = static_cast<char>(toupper(column));  
}    

void printForm(char form[][6], int row, char column)
{
    int i, j;
    
    cout << "* indicates that the seat is available; " << endl; 
    cout << "X indicates that the seat is occupied. " << endl;
    cout << setw(12) << "A" << setw(6) << "B" << setw(6) << "C" 
         << setw(6) << "D" << setw(6) << "E" << setw(6) << "F" << endl;
         
    for(i = 0; i < 13; i++)
    {
       cout << left << setw(3) << "Row " << setw(2)<< i+1 ;
       for(j = 0; j < 6; j++)
       {
           if(i == row - 1 && j == static_cast<int>(column)-65)
              cout << right  << setw(6) << "X";
           else      
              cout << right <<  setw(6) << "*";
             
       }
       cout << endl;  
    }              
}

[Lerner]

Try sending form() to getData() and pass row by copy rather than by reference. Within getData() assign the actual seat number by converting input row number and column char to appropriate index numbers for the array. No need to cast anything that I can think of. It will complicate the getData() function a little, but simplify the print function.

[zalezog]

..problem is after the program works the first time, then the user wants to do it again( which I use a while loop) , for example , choose row 1 B, the form will show X at row 1 B, but not the row 2 A ( which the first time the user chose) any more.
..

that is because int the function

void printForm(char form[][6], int row, char column)

you get into the block only once

if(i == row - 1 && j == static_cast<int>(column)-65)

You don't make the actual change in the

char form[13][6];

Suppose in the beginning, you assume that all the seats are empty and fill a '*' in all the elements of the 2D form[][].You call this function in the beginning of your program itself, something like this:

void initialize( char form[][6])
{
 for(int i=0 ;i < 13 ;i++)
   for(int j=0 ;j<6 ;j++)
     form[i][j]='*';
}
//and call it in the main()  
.
.
.
.
int main()
{
.  
.
char form[13][6];
    initialize( form) ; //empty seat assignment
    cout << "This program assigns seats for a plane.\n"
         << "Do you want to start now? Y/y for yes, N/n for no." << endl;
.
.
  
}

Next you modify the function

void printForm(char form[][6], int row, char column)
{
   //Assign the seat to the OP
  //You can check it seat is already filled
  //by:
  //if ( [static_cast<int>(column)-65]== 'X')
  //{ cout <<"Seat already assigned .Choose another seat";
  // return ;}
  
//Here i make crude assumption that the user enters 
//correct data ,I
//mean rows and columns which are possible ones.
//You don't check that.


//else you assign it
 form[ row-1 ] [static_cast<int>(column)-65]= 'X';
    int i, j;

    cout << "* indicates that the seat is available; " << endl;
    cout << "X indicates that the seat is occupied. " << endl;
    cout << setw(12) << "A" << setw(6) << "B" << setw(6) << "C"
         << setw(6) << "D" << setw(6) << "E" << setw(6) << "F" << endl;
   //Now you display your matrix
    for(i = 0; i < 13; i++)
    {
       cout << left << setw(3) << "Row " << setw(2)<< i+1 ;
       for(j = 0; j < 6; j++)
       {
          cout << right  << setw(6) << form [i][j];
       }
       cout << endl;
    }
}

[YingKang]

Thanks zalezog. I have changed my program according to your suggestion and it works perfectly now. : )

[YingKang]

Here is my updated program which works fine now. I hope it's helpful to others.

#include<iostream>
#include<cctype>
#include<iomanip>

using namespace std;

void initialize( char form[][6]);
void getData(char& ticketType, int& row, 
             char& column);
void printForm(char form[][6], int row, char column);

int main()
{
    char ch, ticketType, column;
    int row;
    char form[13][6];
    
    initialize( form) ;
    cout << "This program assigns seats for a plane.\n"
         << "Do you want to start now? Y/y for yes, N/n for no." << endl;
    cin >> ch;
    
    ch = static_cast<char>(toupper(ch));
    while(ch == 'Y')     
    { 

        getData(ticketType, row, column);
        printForm(form, row, column);
        
        cout << "This program assigns seats for a plane.\n"
             << "Do you want to start now? Y/y for yes, N/n for no." << endl;
        cin >> ch;
        ch = static_cast<char>(toupper(ch));
        if(ch == 'N')
          return 0;     
    }// end while   

    system("PAUSE");
    return 0;
}

void initialize( char form[][6])
{
     for(int i=0 ;i < 13 ;i++)
       for(int j=0 ;j<6 ;j++)
         form[i][j]='*';
}



void getData(char& ticketType, int& row, char& column)
{          
    cout << "The airplane has 13 rows, with  six seats in each row. " << endl;
           
    cout << "Enter ticket type,\n"
         << "F for first class, \n"
         << "B for business class,\n"
         << "E for economy class:" << endl;
    cin >> ticketType;
    ticketType = static_cast<char>(toupper(ticketType));
    while(ticketType != 'F' && ticketType != 'B' 
          && ticketType && ticketType != 'E')
    {
        cout << "Invalid ticket type." << endl;
        cout << "Enter ticket type,\n"
             << "F for first class, \n"
             << "B for business class,\n"
             << "E for economy class:" << endl;
        cin >> ticketType;
        ticketType = static_cast<char>(toupper(ticketType));
     }      
    switch(ticketType)
    {
           case 'F':
                cout <<  "Row 1 and 2 are first class,\n" ;
                break;
           case 'B':
                cout <<  "row 3 throuh 7 are business class,\n";
                break;
           case 'E':
                cout <<  "row 8 through 13 are economy class." << endl; 
                break;
    }// end switch
                
    cout << "Enter the row number you want to sit: " << endl ;
    cin >> row;  
    
    cout << "Enter the seat number (from A to F). " << endl;
    cin >> column;
    column = static_cast<char>(toupper(column));  
    
}    

void printForm(char form[][6], int row, char column)
{
    int i, j;
  
    if(form[row-1][static_cast<int>(column-65)]=='X')
   {
       cout << "This seat already assigned. Choose another seat: " << endl;
       cin >> column;
       column = static_cast<char>(toupper(column));  
   }  
    form[ row-1 ] [static_cast<int>(column)-65]= 'X';
    
    cout << "* indicates that the seat is available; " << endl; 
    cout << "X indicates that the seat is occupied. " << endl;
    cout << setw(12) << "A" << setw(6) << "B" << setw(6) << "C" 
         << setw(6) << "D" << setw(6) << "E" << setw(6) << "F" << endl;
         
    for(i = 0; i < 13; i++)
    {
       cout << left << setw(3) << "Row " << setw(2)<< i+1 ;
       for(j = 0; j < 6; j++)
       {
          cout << right  << setw(6) << form [i][j];
       }
       cout << endl;
    }

}