//******************************************************************* 
//                                                                    
//  Program:  Testints
//                                                                     
//  Description:  Allows user to test integer operations.
//                                                                    
//  Date:  1999/10/1 - latest modification
//
//  Course Information: CS 1711, Laboratory 2
//
//  Filename: testints.cpp 
//                                                                    
//*******************************************************************


#include <iostream.h>
#include <stdlib.h> 

// this function clears the screen
void clrscr(){
	int i;
	for (i = 1; i < 24; i++)
		cout << endl;
}

/* Prints instructions for menu use. */
void DisplayHelp()
{
  clrscr();     // this function clears the screen
  cout << endl;
  cout << "Type the number of your menu selection";
  cout << endl << "and press [Enter].";
  cout << "Your selection must be between 1 and 9" << endl << endl << endl ;
}

/*
	 Prints the menu, prompts the user to make a selection,
	 and then returns the number of that selection
*/
int GetMenuSelection()
{
  int  choice;  /* Users choice. */

  do {
	cout << endl;
	cout << endl << " 1. Help";
	cout << endl << " 2. Set value of A.";
	cout << endl << " 3. Set value of B. " ;
	cout << endl << " 4. Set value of C." ;
	cout << endl << " 5. Display value of A / B";
	cout << endl << " 6. Display value of A % B";
	cout << endl << " 7. Display value of (A % B) % C";
	cout << endl << " 8. Display value of A % (B % C)";
	cout << endl << " 9. Quit";
	cout << endl << endl << endl << endl << endl;
	cout << "Enter the number of your selection " << endl ;

	cin >> choice;

	if ((choice < 1) || (choice > 9)) {
	  cout << ">>>>> Your selection " << choice
	   << " is invalid. <<<<<" << endl;
	}
  } while ((choice < 1) || (choice > 9));
  cout << endl ;
  return(choice) ;
}

int main()
{
  int ExitFlag;   /*: Boolean;  Used to exit program. */
  int A,B,C;      /* Input from the user. */

  clrscr();

  cout << endl << "Begin TestInts ...";

  A=0; B=0; C=0;
  ExitFlag = 0;         /* Initialized to avoid exit of system.   */

  DisplayHelp();

  do {
	switch(GetMenuSelection())   /* display menu/get choice*/
	  {
		case 1: DisplayHelp();
				break;

		case 2: clrscr();
				cout << endl;
				cout << "Enter the value of A:"<< endl ;
				cin >> A;
				clrscr();
				break;

		case 3: clrscr();
				cout << endl;
				cout << "Enter the value of B: "<< endl ;
				cin >> B;
				clrscr();
				break;

		case 4: clrscr();
				cout << endl ;
				cout <<"Enter the value of C: "<< endl ;
				cin >> C ;
				clrscr();
				break;

		case 5: if (B == 0) {
				  clrscr();
				  cout << endl  << "***** Warning! *****";
				  cout << endl  << "Because B = 0";
				  cout << " evaluating A / B ";
				  cout << endl <<"will cause a run time error."<< endl << endl ;
				  break;
				}
				cout << ">>>>> " << A <<" / " << B
					 << " = " << (A / B)
					 << " <<<<<"<< endl << endl ;
				break;

		case 6: if (B == 0) {
				  cout << endl  << "***** Warning! *****";
				  cout << endl  << "Because B = 0";
				  cout << " evaluating A % B ";
				  cout << endl <<"will cause a run time error." << endl << endl ;
				  break;
				}
				cout << ">>>>> " << A <<" % " << B << " = " << (A % B);
				cout << " <<<<<"<< endl << endl ;
				break;

		case 7: if (C == 0) {
				  cout << endl <<"***** Warning! *****";
				  cout << endl  << "Because C = 0";
				  cout          << " evaluating (A % B) % C ";
				  cout << endl << "will cause a run time error."<< endl  << endl;
				  break;
				} //if c=0
				if (B == 0) {
				  cout << endl <<"***** Warning! *****";
				  cout << "Because B = 0";
				  cout << " evaluating (A % B) % C ";
				  cout <<  endl << "will cause a run time error." << endl << endl;
				  break;
				}//if b=0
			  cout << "     >>>>> (" << A << " % " << B << " ) % " << C;
			  cout << " = " << (A % B) % C << " <<<<<" << endl << endl;
			  break;

		case 8: if (C == 0) {
				  cout << "***** Warning! *****\n" ;
				  cout << "Because C = 0";
				  cout << " evaluating A % (B % C) ";
				  cout << endl << "will cause a run time error."<< endl << endl  ;
				  break;
				}
				if ((B % C) == 0) {
				  cout << "***** Warning! *****\n" ;
				  cout << "Because B % C = 0\n";
				  cout << " evaluating A % (B % C) ";
				  cout << "will cause a run time error."<< endl << endl ;
				  break;
				}
				cout << "     >>>>> " << A << " % (" << B
					 << "  % " << C << " )"
					 << " = " << A % (B % C) << " <<<<<" << endl << endl;
				break;

		case 9: ExitFlag = 1;

	  } // endswitch
  } while (ExitFlag == 0);

  clrscr();
  cout << endl << endl << "End TestInts." << endl;
  return(0);
}