// FILE: str_demo.cxx
// Written by Shivakant Mishra
// Last Update: February 22, 2008
// This is a demonstration program showing how the string functions are used.
#include <iostream>     // Provides cout and cin
#include <cstdlib>      // Provides EXIT_SUCCESS

using namespace std;

void print_menu( );
char get_user_command( );
typedef char* mystring; 

int main( )
{
    mystring *str; //Array of strings;
    size_t count = 0;

    cout << "Enter the size of your string array (an integer > 0): ";
    int sz;
    cin >> sz;
    assert (sz > 0);
    str = new mystring[sz]; //str is an array of size sz

    cout << "I have initialized an empty string array of size" << sz << endl;

    char choice, s1[100], s2[100];
    int i, cn = 0;
    bool flag = false;
    do
    {
        print_menu( );
        choice = toupper(get_user_command( ));
        switch (choice)
        {
            case 'I': cin >> s1;
		      if (count != sz) {
	  	          str[count] = new char[strlen(s1) + 1];
		          strcpy(str[count], s1);
		          count++;
			  cout << "String <" << s1 << "> has been inserted in the string array" << endl;
		      }
		      else cout << "String array is full" << endl;
                      break;
            case '?': cin >> s1;
		      for (i = 0; i < count; i++)
		          if (strcmp(str[i], s1) == 0) {
			     cout << "String <" << s1 << "> is present in the string array" << endl;
			     break;
			  }
		      if (i == count)
	       	          cout << "String <" << s1 << "> is not present in the string array" << endl;
                      break;
            case 'C': cout << "There are " << count << " strings in the string array" << endl;
                      break;
            case 'P': for (i = 0; i < count; i++)
		          cout << str[i] << endl;
                      break;
            case 'R': cin >> s1;
		      for (i = 0; i < count; i++) {
		          if (strcmp(str[i], s1) == 0) {
			      delete [] str[i];
			      str[i] = str[count-1];
			      count--;
			      cout << "One occurrence of <" << s1 << "> has been removed" << endl;
			      flag = true;
			      break;
		          }
		      }
		      if (!flag)
	       	          cout << "String <" << s1 << "> is not present in the string array" << endl;
		      flag = false;
                      break;
            case '<': cin >> s1;
		      cout << "Strings in the string array that are less than <" << s1 << "> are:" << endl;
		      for (i = 0; i < count; i++)
			  if (strcmp(str[i], s1) < 0) cout << str[i] << endl;
                      break;
            case 'S': cin >> s1 >> s2;
		      for (i = 0; i < count; i++)
		          if (strcmp(str[i], s1) == 0) {
			      delete [] str[i];
			      str[i] = new char[strlen(s2) + 1];
			      strcpy(str[i], s2);
			      cout << "One occurrence of <" << s1 << "> has been substituted by <" << s2 << ">" << endl;
			      break;
			  }
		      if (i == count)
	       	          cout << "String <" << s1 << "> is not present in the string array" << endl;
                      break;
            case 'A': cin >> s1 >> s2;
		      for (i = 0; i < count; i++)
		          if (strcmp(str[i], s1) == 0) {
			      delete [] str[i];
			      str[i] = new char[strlen(s2) + 1];
			      strcpy(str[i], s2);
			      cn++;
			  }
		      cout << cn << " occurrence of <" << s1 << "> has/have been substituted by <" << s2 << ">" << endl;
		      cn = 0;
                      break;
            case 'Q': cout << "The demo program has ended." << endl;
                      break;
            default:  cout << choice << " is invalid." << endl;
       }
    }
    while ((choice != 'Q'));

    return EXIT_SUCCESS; 
}

void print_menu( )
// Library facilities used: iostream.h
{
    cout << endl; // Print blank line before the menu
    cout << "The following choices are available (A string ends with a white space): " << endl;
    cout << " I <string> : Insert <string> in the string array" << endl;
    cout << " ? <string> : Is <string> available in the string array?" << endl;
    cout << " C : Print the number of strings in the string array" << endl;
    cout << " P : Print all strings in the string array" << endl;
    cout << " R <string> : Remove <string> from the string array" << endl;
    cout << " < <string> : Print all strings from the string array that are smaller than <string>" << endl;
    cout << " S <string1> <string2> : Substitute one occurrence of <string1> with <string2>" << endl;
    cout << " A <string1> <string2> : Substitute all occurrences of <string1> with <string2>" << endl;
    cout << " Q : Quit this test program" << endl;
    cout << endl; // Print blank line after the menu
}

char get_user_command( )
// Library facilities used: iostream
{
    char command;

    cout << "Enter choice: ";
    cin >> command; // Input of characters skips blanks and newline character

    return command;
}