//-----------------------------------------------------------------------------
// FILE: author.cxx
// A demonstration program showing how the vector template class is used.
// The program reads some words into vectors of strings.
// Then a silly story is written using these words.
#include <cassert>    // Provides assert
#include <iostream>   // Provides cout and cin
#include <cstdlib>    // Provides EXIT_SUCCESS and rand
#include <string>     // Provides string class
#include <vector>     // Provides the vector template class
using namespace std;
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
const size_t ITEMS_PER_VECTOR = 4;  // Number of items to put into each vector
const size_t MANY_SENTENCES = 3; // Number of sentences in the silly story
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// PROTOTYPES
// Prompt the user to read n strings that are described by description,
// and put those strings into the vector.
void get_items(vector<string>& collection, size_t n, string description);

// Precondition: v.size( ) > 0;
// The return value is a random string selected from v
string random(vector<string> v);
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
int main( )
{
    vector<string> adjectives;  // Contains adjectives typed by user
    vector<string> ages;        // Contains ages in the teens typed by user
    vector<string> names;       // Contains names typed by user 
    size_t line_number;         // Number of the output line

    // Fill the three vectors with items typed by the program's user.
    cout << "Help me write a story.\n";
    get_items(adjectives, ITEMS_PER_VECTOR, "adjectives that describe a mood");
    get_items(ages,       ITEMS_PER_VECTOR, "integers in the teens");
    get_items(names,      ITEMS_PER_VECTOR, "first names");
    cout << "Thank you for your kind assistance.\n\n";

    // Use the items to write a silly story.
    cout << "LIFE\n";
    cout << "by A. Computer\n";
    for (line_number = 0; line_number < MANY_SENTENCES; ++line_number)
    {
	cout << random(names)
	     <<" was only " 
	     << random(ages)
	     << " years old, but he/she was "
	     << random(adjectives)
	     << "." << endl;;
    }
    cout << "Life is " << random(adjectives) << "." << endl;
    cout << "The (" << random(adjectives) << ") end" << endl;

    return EXIT_SUCCESS;
}
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
void get_items(vector<string>& collection, size_t n, string description)
{
    string user_input; // An item typed by the program's user

    cout << "Please type " << n << " " << description;
    cout << ", separated by spaces.\n";
    cout << "Press the <return> key after the final entry:\n";
    do
    {
        cin >> user_input;
        collection.push_back(user_input);
	--n;
    }   while (n > 0);
    cout << endl;
}
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
string random(vector<string> v)
{
    assert(v.size( ) > 0);
    return v[rand() % v.size( )];
}
//-----------------------------------------------------------------------------