Question

I am having problems with my program. WHen I run it, it asks the user for the album, the title, but then it just exits the loop without asking for the price and the sale tax. Any ideas what’s going on?

This is a sample run

Discounts effective for September 15, 2010
Classical   8%
Country 4%
International   17%
Jazz    0%
Rock    16%
Show    12%
Are there more transactions? Y/N
y
Enter Artist of CD: 
Sevendust
Enter Title of CD: 
Self titled
Enter Genre of CD: 
Rock
enter price
Are there more transactions? Y/N
Thank you for shopping with us!

Program code:

#include <iostream>

#include <string>



using namespace std;



int counter = 0;

string discount_tiles[] = {"Classical", "Country", "International", "Jazz", "Rock", "Show"};

int discount_amounts[] = {8, 4, 17, 0, 16, 12, 14};

string date = "September 15, 2010";



// Array Declerations

    //Artist array

    char** artist = new char *[100];        

    //Title array

    char** title = new char *[100]; 

    //Genres array

    char** genres = new char *[100];

    //Price array

    double* price[100]; 

    //Discount array

    double* tax[100];

    // sale price array

    double* sale_price[100];    

    //sale tax array

    double* sale_tax[100];  

    //cash price array

    double* cash_price[100];    



//Begin Prototypes

char* getArtist();

char* getTitle();

char* getGenre();

double* getPrice();

double* getTax();

unsigned int* AssignDiscounts();

void ReadTransaction (char ** artist, char ** title, char ** genre, float ** cash, float & taxrate, int albumcount);

void computesaleprice();





bool AreThereMore ();



//End Prototypes



bool areThereMore ()

{   

    char answer;

    cout << "Are there more transactions? Y/N" << endl;

    cin >> answer;

    if (answer =='y' || answer =='Y')

        return true;

    else 

        return false;

}



char* getArtist()

{

    char * artist= new char [100];

    cout << "Enter Artist of CD: " << endl;

    cin.getline(artist,100);

    cin.ignore();

    return artist;

}



char* getTitle()

{

    char * title= new char [100];

    cout << "Enter Title of CD: " << endl;

    cin.getline(title,100);

    cin.ignore();

    return title;

}



char* getGenre()

{

    char * genre= new char [100];

    cout << "Enter Genre of CD: " << endl;

    cin.getline(genre,100);

    cin.ignore();

    return genre;

}



double* getPrice()

{   

    //double* price = new double();

    //cout << "Enter Price of CD: " << endl;

    //cin >> *price;



    //return price;



    double p = 0.0;

    cout<< "enter price" << endl;

    cin >> p;

    cin.ignore();

    double* pp = &p;

    return pp;

}



double* getTax()

{

    double* tax= new double();

    cout << "Enter local sales tax: " << endl;

    cin >> *tax;



    return tax;

}



int findDiscount(string str){



    if(str.compare(discount_tiles[0]) == 0)

        return discount_amounts[0];

    else if(str.compare(discount_tiles[0]) == 0)

        return discount_amounts[1];

    else if(str.compare(discount_tiles[0]) == 0)

        return discount_amounts[2];

    else if(str.compare(discount_tiles[0]) == 0)

        return discount_amounts[3];

    else if(str.compare(discount_tiles[0]) == 0)

        return discount_amounts[4];

    else if(str.compare(discount_tiles[0]) == 0)

        return discount_amounts[5];

    else{

        cout << "Error in findDiscount function" << endl;

        return 0;

    }

}



void computesaleprice()

{

    /** fill in array for all purchases **/

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

        double temp = *price[i];

        temp -= findDiscount(genres[i]);

        double* tmpPntr = new double();

        tmpPntr = &temp;

        sale_price[i] = tmpPntr;

        delete(&temp);

        delete(tmpPntr);

    }

}











void printDailyDiscounts(){

    cout << "Discounts effective for " << date << endl;

    for(int i=0; i < 6; i++){

        cout << discount_tiles[i] << "\t" << discount_amounts[i] << "%" << endl;

    }

}



//Begin Main

int main ()

{







    for( int i=0; i<100; i++){

        artist[i]=new char [100];

        title[i]=new char [100];

        genres[i]=new char [100];       

        price[i] = new double(0.0);

        tax[i] = new double(0.0);

    }



    // End Array Decleration



    printDailyDiscounts();



    bool flag = true;   

    while(flag == true){

        if(areThereMore() == true){

            artist[counter] = getArtist();

            title[counter] = getTitle();

            genres[counter] = getGenre();

            price[counter] = getPrice();

            //tax[counter] = getTax();          

            //counter++;

            flag = true;

        }

        else {

            flag = false;

        }

    }





    //compute sale prices

    //computesaleprice();













    cout << "Thank you for shopping with us!" << endl;



    return 0;

}

//End Main













/**

void ReadTransaction (char ** artist, char ** title, char ** genre, float ** cash, float & taxrate, int albumcount)

{

    strcpy(artist[albumcount],getArtist());

    strcpy(title[albumcount],getTitle());

    strcpy(genre[albumcount],getGenre());

    //cash[albumcount][0]=computesaleprice();???????

    //taxrate=getTax;??????????????





}

* 

* */







unsigned int * AssignDiscounts()

{

    unsigned int * discount = new unsigned int [7];

    cout << "Enter Classical Discount: " << endl;

    cin >> discount[0];

    cout << "Enter Country Discount: " << endl;

    cin >> discount[1];

    cout << "Enter International Discount: " << endl;

    cin >> discount[2];

    cout << "Enter Jazz Discount: " << endl;

    cin >> discount[3];

    cout << "Enter Pop Discount: " << endl;

    cin >> discount[4];

    cout << "Enter Rock Discount: " << endl;

    cin >> discount[5];

    cout << "Enter Show Discount: " << endl;

    cin >> discount[6];

    return discount;

}



/**

char ** AssignGenres ()

{

    char ** genres = new char * [7];

    for (int x=0;x<7;x++)

        genres[x] = new char [20];

    strcpy(genres [0], "Classical");

    strcpy(genres [1], "Country");

    strcpy(genres [2], "International");

    strcpy(genres [3], "Jazz");

    strcpy(genres [4], "Pop");

    strcpy(genres [5], "Rock");

    strcpy(genres [6], "Show");

    return genres;

}

**/







float getTax(float taxrate)

{

    cout << "Please enter store tax rate: " << endl;

    cin >> taxrate;

    return taxrate;

}

Answer 1

You are returning a pointer to a local variable from getPrice:

double* getPrice()
{   
    double p = 0.0;
    cout<< "enter price" << endl;
    cin >> p;
    cin.ignore();
    double* pp = &p;
    return pp;
}

Since p goes out of scope (i.e. gets destroyed) when you return from the function, you get a dangling pointer, which results in undefined behaviour.

Sale tax is not asked for because the call to getTax() is commented out.