Thread: trying to get a few functions to work properly...

Hey all,

Im pretty new to c++ and alot of the constructs I am using in this program - strings, functions, pointers, arrays, structures etc.

The main below is fleshed out and is compiling correctly. I am having difficulty passing around values and getting my three functions in this program to work properly. I have the arguments and parameters allready set up for each function as a skeleton and I have commented in each of the three functions what I am trying to get them to do.

Any help w/my functions is greatly appreciated!

Code:

/////////////////////////////////
//       WORK IN PROGRESS     //
////////////////////////////////
//compilable



// This is a program for "renting" movies. There are only two movies that will be used in the
// program - Jurassic Park & Lord of the Rings. The user can do a search for a movie
// (only Jurassic Park or Lord of the Rings will produce a result as they are the 
// only ones that will be used for the time being), view all the movies 
// not currently "rented", and then proceed to "rent" a movie 
// thus making it unavailable at that point. Each option corresponds
// to a function set up in the 
// selection menu set up in main.



#include <iostream>




using namespace std;




struct movie_structure {
       char movie_name[40];
       char director[40];
       char product_number[10];
       bool rented;
};


void rent_movie (movie_structure* movie)
{
//Will "rent" a movie making it no longer available (i.e. set boolean value to true)
}


movie_structure* get_movie (movie_structure movie_library[], char* movie_name, int library_size)
{
//will return a pointer to a movie based on title supplied, else will return null pointer
}


void print_movies_available (movie_structure movie_library[], int library_size)
{   
//will display the movies not currently "rented" (i.e. movies w/false boolean value) 
}

  
int main()
{
    char user_input_title[81]; // user's input
    movie_structure* movie; // movie pointer 
    int selection = 0;   // for the menu selections
    int number_of_movies = 2;  // number of movies in the 'movie library'
                
                                           
    movie_structure movie_library[] = {  //title               //director          //product #'s   //boolean value
                                         {"Jurassic Park",     "Steven Spielberg", "913564180",     0},
                                         {"Lord of the Rings", "Peter Jackson",    "376145212",     0}
                                      };
                                     
    cout<<"*******************************"<<endl;  
    cout<<"*                             *"<<endl;
    cout<<"* WELCOME TO THE VIDEO STORE! *"<<endl;
    cout<<"*                             *"<<endl;
    cout<<"*******************************"<<endl<<endl;
    
    do{
       cout<<"OPTIONS:"<<endl<<endl;
       cout<<"1 - Search for a movie."<<endl<<endl;
       cout<<"2 - View all available movies."<<endl<<endl;
       cout<<"3 - Rent a movie."<<endl<<endl;
       cout<<"4 - Exit store."<<endl<<endl;
       cout<<"SELECTION: ";
       cin>>selection;
       cout<<endl;
       
       if(cin.good() && selection > 0 && selection < 5){
                     
         if(selection == 1 || selection == 3){//selections that require a movie title
           cin.ignore();
           cout<<"Enter the title of the movie."<<endl<<"Title: ";
           
           cin.getline(user_input_title,81);
           
           movie = get_movie(movie_library, user_input_title, number_of_movies);  
           
           if (movie == NULL)  //invalid title
                cout<<endl<<user_input_title<<" not found. Try again."<<endl<<endl;
    
           else if (movie->rented == true) //valid movie, but movie is currently "rented"
                cout<<movie->movie_name<<" is checked out. Sorry!"<<endl<<endl;
                
           else if (selection == 1) //movie available for "rent"
                cout<<endl<<movie->movie_name<<" by "<<movie->director<<" is available."<<endl<<endl;
                
           else{  //movie available
                 cout<<endl<<movie->movie_name<<" is available. Let me check it out for you!"<<endl<<endl;
                 rent_movie(movie);
              }
           }
           
         else if(selection == 2){ //selection 2 will print all movies available
            print_movies_available(movie_library, number_of_movies); 
         }
         
         else {
           cout<<"Goodbye."<<endl;
           return 0;
         }
       }
       
       else {   //invalid selection
          cout<<endl<<"Invalid selection."<<endl<<endl;
          selection = 1;
       }
     }
     while(selection < 4);
    return 0;
}

Any input, tips, or coding ideas?

Thanks for your help!

Basically I think you just need to know about search algorithms to do this.

Cprogramming.com - Discussion Articles - Efficient Searching from Sequential to Binary Search and Beyond

Well since your limited to only two movies, I'd say a linear search wold suffice which loops through all elements in your structure and sees if there is a match to the one you are currently looking for.