First C++ App!!!

Heres my first c++ app.
Tell me what you think.:D

Code:

---

#include <iostream.h>

int main()
{

char vPick1;
char vPick2;
double vNum1;
double vNum2;
double vAnswer;

start:
    cout << "\n\n***************************";
    cout << "\n*******Calc-4U-Later*******";
    cout << "\n*Written by : Ryan Nielson*";
    cout << "\n***************************\n\n";


    cout << "\n\nWould you like to [a]dd, [s]ubtract, [m]ultiply or [d]ivide : ";
    cin >> vPick1;
if (vPick1 == 'a')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will add them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 + vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 's')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will subtract them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 - vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 'm')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will multiply them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 * vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 'd')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will divide them : ";
    cin >> vNum1;
    cin >> vNum2;
    vAnswer = vNum1 / vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
    cout << "\n\nWould you like to [c]ontinue or [e]xit ? : ";
    cin >> vPick2;
if (vPick2 == 'c')
{
    goto start;
}
else
{
    return 0;
}
}

---

BEFORE YOU DO ANYTHING ELSE, remove the word "goto" from your vocabulary.

Code:

---

    cout << "\n\nWould you like to [c]ontinue or [e]xit ? : ";
    cin >> vPick2;
if (vPick2 == 'c')
{
    goto start;
}
else
{
    return 0;
}

---

use a loop for this. seems like you want to run the prog at least once so use a do while loop.

Whats wrong with goto?

Code:

---

#include <iostream.h>

int main()
{


char vPick1;
char vPick2 = 'c';
double vNum1;
double vNum2;
double vAnswer;

while (vPick2)
{
    cout << "\n\n***************************";
    cout << "\n*******Calc-4U-Later*******";
    cout << "\n*Written by : Ryan Nielson*";
    cout << "\n***************************\n\n";


    cout << "\n\nWould you like to [a]dd, [s]ubtract, [m]ultiply or [d]ivide : ";
    cin >> vPick1;
if (vPick1 == 'a')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will add them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 + vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 's')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will subtract them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 - vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 'm')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will multiply them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 * vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 'd')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will divide them : ";
    cin >> vNum1;
    cin >> vNum2;
    vAnswer = vNum1 / vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
    cout << "\n\nWould you like to [c]ontinue or [e]xit ? : ";
    cin >> vPick2;

}
}

---

There i added a while loop.
Hows that now?

Quote:

---

Whats wrong with goto?

---

There isnt anything WRONG w/ goto. It is perfectly legal in C++. the bad thing about it is that it is just bad programming. usually 99.9% of the time there is a easier way and a better way of doing something than using goto. it is also difficult to read code w/ goto b/c you have to look all over the place. for your sake just avoid it.

Quote:

---

Originally posted by TWIXMIX
There i added a while loop.
Hows that now?

---

Well, since you asked....

Generally, it's not bad at all. Now on to the nitpicking ;)

1) Format properly. Every { you use should indent everything after it to the matching } -- including the one after main()

2) Every one of your if()'s is constructed:

Code:

---

if (vPick1 == val)
{
    output "*** text about entering 2 numbers***: ";
    input Num1
    input Num2
    calculate answer
    output answer
}

---

This is very redundant. If you think about it a little, I'll bet you can shorten your code by over 75%.

3) What happens if the CAPS-LOCK is on?

4) Have you gotten to the switch() statement yet?

very well done, suggestions: drop goto, and use a switch statment.

Looks like you have done really well mate, people are right about goto it will make your life easier not using it, but your layout looks fine to me, I found it well easy to read.

more nitpicking... most of this has been covered by other members, except (I think) the iostream part...

Code:

---

//#include <iostream.h>
//should be
#include <iostream>
using namespace std; //good enough for now

int main()
{

char vPick1;
char vPick2;
double vNum1;
double vNum2;
double vAnswer;

start:
    cout << "\n\n***************************";
    cout << "\n*******Calc-4U-Later*******";
    cout << "\n*Written by : Ryan Nielson*";
    cout << "\n***************************\n\n";


    cout << "\n\nWould you like to [a]dd, [s]ubtract, [m]ultiply or [d]ivide : ";
    cin >> vPick1;
if (vPick1 == 'a') //and if the enter 'A'?
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will add them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 + vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 's') //try an 'else if'
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will subtract them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 - vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 'm')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will multiply them : ";
    cin >> vNum1;
    cin>> vNum2;
    vAnswer = vNum1 * vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
}
if (vPick1 == 'd')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will divide them : ";
    cin >> vNum1;
    cin >> vNum2;
    vAnswer = vNum1 / vNum2;
    cout << "\n\nThe answer is : " << vAnswer;
} //and if they enter 'Z'?
    cout << "\n\nWould you like to [c]ontinue or [e]xit ? : ";
    cin >> vPick2;

/***  Personal Preference: change this ***
if (vPick2 == 'c')
{
    goto start;
}
*** to this ***/

if(vPick2=='c')
  goto start; //avoid goto like the plague

/*** try not to encapsulate a return ***
else
{
    return 0;
}
*** this does the same thing ***/
return 0;
}

---

When you get to functions and switches a good place to practise them on is this program. Keep going ;)

Alright guys thanks alot for the comments and help

Now it doesnt work.
I shortened my code up and that works fine but now when you type 'e' and the end to exit it loops bad around instead of exiting.

Also how do I make the program so it doesn't matter weither you type capital or lower-case latter?

Can someone please help!:D

Code:

---

#include <iostream>
using namespace std;

int main()
{
char vPick1;
char vPick2 = 'c';
double vNum1, vNum2, vAnswer;

while (vPick2)
{
    cout << "\n\n***************************";
    cout << "\n*******Calc-4U-Later*******";
    cout << "\n*Written by : Ryan Nielson*";
    cout << "\n***************************\n\n";
    cout << "\n\nWould you like to [a]dd, [s]ubtract, [m]ultiply or [d]ivide : ";
    cin >> vPick1;
if (vPick1 == 'a')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will add them : ";
    cin >> vNum1 >> vNum2;
    vAnswer = vNum1 + vNum2;
}
if (vPick1 == 's')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will subtract them : ";
    cin >> vNum1 >> vNum2;
    vAnswer = vNum1 - vNum2;
}
if (vPick1 == 'm')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will multiply them : ";
    cin >> vNum1 >> vNum2;
    vAnswer = vNum1 * vNum2;
}
if (vPick1 == 'd')
{
    cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will divide them : ";
    cin >> vNum1 >> vNum2;
    vAnswer = vNum1 / vNum2;
}
    cout << "\n\nThe answer is : " <<vAnswer;
    cout << "\n\n\nWould you like to [c]ontinue or [e]xit ? : ";
    cin >> vPick2;
}
return 0;

}

---

A quick glance at your code... made a few changes. Go through it and compare it to yours.

Code:

---

#include <iostream>
using namespace std;

int main()
{
  char vPick1;
  double vNum1, vNum2, vAnswer;

  do {
      cout << "\n\n***************************";
      cout << "\n*******Calc-4U-Later*******";
      cout << "\n*Written by : Ryan Nielson*";
      cout << "\n***************************\n\n";
      cout << "\n\nWould you like to [a]dd, [s]ubtract, [m]ultiply or [d]ivide: ";
      cin >> vPick1;
     
      if (vPick1 == 'a')
      {
        cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will add them : ";
        cin >> vNum1 >> vNum2;
        vAnswer = vNum1 + vNum2;
      }
      else if (vPick1 == 's')
      {
          cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will subtract them : ";
          cin >> vNum1 >> vNum2;
          vAnswer = vNum1 - vNum2;
      }
      else if (vPick1 == 'm')
      {
          cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will multiply them : ";
          cin >> vNum1 >> vNum2;
          vAnswer = vNum1 * vNum2;
      }
      else if (vPick1 == 'd')
      {
          cout << "\n\nPlease enter 2 numbers spaced apart and the calculator will divide them : ";
          cin >> vNum1 >> vNum2;
          vAnswer = vNum1 / vNum2;
      }
      cout << "\n\nThe answer is : " <<vAnswer;
      cout << "\n\n\nWould you like to [c]ontinue or [e]xit ? : ";
      cin >> vPick1;
  }  while ( (vPick1 != 'e') && (vPick1 != 'E') );
 
  return 0;
}

---

:cool:

nevermind it works.
Thanks alot man i appretiate it