Script started on Sat Aug 24 12:22:55 2002
$ cat math.info
/**************************************************************************
 *                                                                        *
 *  NAME:  Jason James                            CLASS:  CSC121-00x      *
 *                                                                        *
 *  Lab:  MATH!!!                                 Level:  0               *
 *                                                                        *
 *  Description:                                                          *
 *                                                                        *
 *     This program reads two numbers from the user.  Once read in, we    *
 *  perform the four basic math operations (addition, subtraction,        *
 *  multiplication, and division) on them and display the results in a    *
 *  traditional format.                                                   *
 *                                                                        *
 **************************************************************************/
$ cat math.cpp
// include input/output streams support code
#include <iostream>

// use identifiers (functions, etc.) from the standard name space
using namespace std;

// main program -- where it all happens!
int main(void)
{
    double number1, number2;   // two numbers input by the user

    // greet user
    cout << "Welcome to the Math Calculation Program!!!\n" << endl;

    // prompt for and read in two values
    cout << "Please enter your two numbers:  ";
    cin >> number1 >> number2;

    // let the user know we got their values and are working on it
    cout << "Thank you!!  You've entered " << number1
         << " and " << number2 << "!  Calculating...\n\nDone.\n" << endl;

    // print resulting calculations in a nice format
    cout << number1 << " + " << number2 << " = " << (number1 + number2) << endl
         << number1 << " - " << number2 << " = " << (number1 - number2) << endl
         << number1 << " * " << number2 << " = " << (number1 * number2) << endl
         << number1 << " / " << number2 << " = " << (number1 / number2) << endl;

    // thank the user and say goodbye...
    cout << "Thank you for using the MCP!!\n\n"
         << "Endeavor to have a advantageous day!" << endl;

    // return control to the Operating System
    return 0;
}
$ CPP math
math.cpp***


$ ../math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  12 42
Thank you!!  You've entered 12 and 42!  Calculating...

Done.

12 + 42 = 54
12 - 42 = -30
12 * 42 = 504
12 / 42 = 0.285714
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  -12 42
Thank you!!  You've entered -12 and 42!  Calculating...

Done.

-12 + 42 = 30
-12 - 42 = -54
-12 * 42 = -504
-12 / 42 = -0.285714
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  12 -42
Thank you!!  You've entered 12 and -42!  Calculating...

Done.

12 + -42 = -30
12 - -42 = 54
12 * -42 = -504
12 / -42 = -0.285714
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  12
42
Thank you!!  You've entered 12 and 42!  Calculating...

Done.

12 + 42 = 54
12 - 42 = -30
12 * 42 = 504
12 / 42 = 0.285714
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  -12 -42
Thank you!!  You've entered -12 and -42!  Calculating...

Done.

-12 + -42 = -54
-12 - -42 = 30
-12 * -42 = 504
-12 / -42 = 0.285714
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  -42 -12
Thank you!!  You've entered -42 and -12!  Calculating...

Done.

-42 + -12 = -54
-42 - -12 = -30
-42 * -12 = 504
-42 / -12 = 3.5
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  42 12
Thank you!!  You've entered 42 and 12!  Calculating...

Done.

42 + 12 = 54
42 - 12 = 30
42 * 12 = 504
42 / 12 = 3.5
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  0 12
Thank you!!  You've entered 0 and 12!  Calculating...

Done.

0 + 12 = 12
0 - 12 = -12
0 * 12 = 0
0 / 12 = 0
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  12 0
Thank you!!  You've entered 12 and 0!  Calculating...

Done.

12 + 0 = 12
12 - 0 = 12
12 * 0 = 0
12 / 0 = inf
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  -12 0
Thank you!!  You've entered -12 and 0!  Calculating...

Done.

-12 + 0 = -12
-12 - 0 = -12
-12 * 0 = -0
-12 / 0 = -inf
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ ./math.out
Welcome to the Math Calculation Program!!!

Please enter your two numbers:  0 0
Thank you!!  You've entered 0 and 0!  Calculating...

Done.

0 + 0 = 0
0 - 0 = 0
0 * 0 = 0
0 / 0 = nan
Thank you for using the MCP!!

Endeavor to have a advantageous day!
$ cat math.tpq
  1) How many cin statements do you need in this program?

     One.  cin skips any intervening spaces and so we can read both
     variables values with a single cin statement.

  2) Should the "welcome" and the "enter" be printed from the same
     cout statement?

     They can be, but they probably shouldn't be.  They are two separate
     logical ideas and so should be two separate statements.

  3) What happens if the user types their numbers on separate lines
     (instead of simply separated by spacing as above)?

     That's fine.  Any spacing -- even a new-line -- will do to separate
     the two variables' values.

  4) Obviously if your variables for the user's numbers are float or double,
     the division answer will have decimal places.  Can you still get a
     floating point answer even if you are using whole valued variables for
     the user's numbers?

     Yes.  You can use a typecast to make at least one of them floating
     point for the duration of the division:

         long number1, number2;

         cout << number1 << " / " << number2 << " = "
              << ( static_cast<double>(number1) / number2 ) << endl;

  5) How many variables do you need for this program at a minimum?

     Two -- one for each input.

     At most?

     I couldn't see using more than 6.  One for each input and one for
     each calculation.

  6) What happens if the user's values are of different signs?  Both
     negative?  In descending order?  The same?

     All of the calculations work on any pair of real numbers -- just
     like in mathematics.

  7) What happens if the user's first value is a 0?

     Everything works fine when the first value is a 0.

     Their second value?

     All calculations work fine...except division.  When dividing
     by 0, mathematics says the result is undefined.  The computer,
     however, defines the result as either INFinity (if the dividend
     is positive), -INFinity (if the dividend is negative), or Not-A-
     Number (if the dividend is also 0).
$ exit
Script done on Sat Aug 24 12:25:06 2002