TRY IT OUT Manipulating Variables with Mathematical Operators

bargeanimal · July 22nd, 2010, 08:05 AM

Hi,

I've just typed in the following piece of code from chapter 3 page 47 of Beginning Visual C# 2010. From the very first line "static void Main(string[] args)", I get the following errors:
void = expected class, delegate, enum, interface or struct
on the [] after string, I get "Identifier Expected"
arg = expected class, delegate, enum, interface or struct
Those are the same errors I get if I try to compile it with CSC. I can't see any other errors in the code. Here's a copy of my code. I would really appreciate if anyone can offer me any assistance or show me where I'm going wrong. Thanks very much!!!

static void Main(string[] args)
{
double firstNumber, secondNumber;
string userName;
Console.WriteLine("Enter Your Name:");
userName = Console.ReadLine();
Console.WriteLine("Welcome {0}!", userName);
Console.WriteLine("Now Give Me A Number");
firstNumber = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("Now Give Me Another Number:");
secondNumber = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("The Sum of {0} and {1} is {2}.", firstNumber,
secondNumber, firstNumber + secondNumber);
Console.WriteLine("The Product of {0} and {1} is {2}", firstNumber,
secondNumber, firstNumber * secondNumber);
Console.WriteLine("The Result of Dividing {0} by {1} is {2}.",
firstNumber, secondNumber, firstNumber / secondNumber);
Console.WriteLine("The Remainder after Dividing {0} by {1} is {2}.",
firstNumber, secondNumber, firstNumber % secondNumber);]
Console.Readkey();

}

joefawcett · July 22nd, 2010, 10:18 AM

Sounds like you're missing brace somewhere. Try creating a new class and pasting the example over the skeleton provided.

bargeanimal · July 22nd, 2010, 11:20 AM

Quote:

Originally Posted by joefawcett

Sounds like you're missing brace somewhere. Try creating a new class and pasting the example over the skeleton provided.

Hi Joe,

Please excuse my ignorance but I'm a beginner. I'm not quite sure if I've followed your advice correctly but here's what I've done and it's really gone off on one now:)

Thanks very much for your help:)

static Main(string[] args)
{

{
public class prog1() ; (with and without the parentesis and the semi colon)
double firstNumber, secondNumber;
string userName;
Console.WriteLine("Enter Your Name:");
userName = Console.ReadLine();
Console.WriteLine("Welcome {0}!", userName);
Console.WriteLine("Now Give Me A Number");
firstNumber = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("Now Give Me Another Number:");
secondNumber = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("The Sum of {0} and {1} is {2}.", firstNumber,
secondNumber, firstNumber + secondNumber);
Console.WriteLine("The Product of {0} and {1} is {2}", firstNumber,
secondNumber, firstNumber * secondNumber);
Console.WriteLine("The Result of Dividing {0} by {1} is {2}.",
firstNumber, secondNumber, firstNumber / secondNumber);
Console.WriteLine("The Remainder after Dividing {0} by {1} is {2}.",
firstNumber, secondNumber, firstNumber % secondNumber);]
Console.Readkey();

}

}

bargeanimal · July 23rd, 2010, 07:30 AM

Surely someone must have an answer for this. It's only a basic program from chapter 3 in a beginner's C# book.

Imar · July 23rd, 2010, 07:40 AM

Hi there,

You need to add your code to a class, like this:

Code:

 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
 class Program
 {
  static void Main(string[] args)
  {
    double firstNumber, secondNumber;
    string userName;
    Console.WriteLine("Enter Your Name:");
    // Rest of your code here
  }
 }
}

Hope this helps,

Imar

samjudson · July 23rd, 2010, 08:44 AM

Firstly, we don't have the book you are referring to.

Secondly, you have posted to a C# 1.0 forum, when the book you are referring to is a C# 4.0 topic. Also each book should have its own forum where hopefully the author, or at least people who have access to the book are watching.

Thirdly, have you tried downloading to books source code. Maybe this contains the example you are trying to type in and you can spot the differences.

Finally, as Imar says your Main method should be inside a class, and that probably inside a namespace. Usually there are those using statements at the top.

bargeanimal · July 23rd, 2010, 11:37 AM

Thanks a million Imar. That did the trick! Many many thanks!!!

oldSqlNewToC · September 8th, 2010, 05:29 PM

Quote:

Originally Posted by bargeanimal

Surely someone must have an answer for this. It's only a basic program from chapter 3 in a beginner's C# book.

Learning C# for 1st time and using and on pg 48 of 1037 and Ch03Ex02 from the book and downloaded code the division operator is not working as expected for me...

Welcome... give#1(5)
give#2(5)

each math answer works except the last one:

Code:

onsole.WriteLine("The result of dividing {0} by {1} is {2}.",
                firstNumber, secondNumber, firstNumber % secondNumber);

It returns as

Quote:

The result of dividing 5 by 5 is 0.

Code:

#region Using D's

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

#endregion

namespace Ch03Ex02
{
    class Program
    {
        static void Main(string[] args)
        {
            double firstNumber, secondNumber;
            string userName;
            Console.WriteLine("Enter your name:");
            userName = Console.ReadLine();
            Console.WriteLine("Welcome {0}!", userName);
            Console.WriteLine("Now give me a number:");
            firstNumber = Convert.ToDouble(Console.ReadLine());
            Console.WriteLine("Now give me another number:");
            secondNumber = Convert.ToDouble(Console.ReadLine());
            Console.WriteLine("The sum of {0} and {1} is {2}.", firstNumber,
                secondNumber, firstNumber + secondNumber);
            Console.WriteLine("The result of subtracting {0} from {1} is {2}.",
                secondNumber, firstNumber, firstNumber - secondNumber);
            Console.WriteLine("The product of {0} and {1} is {2}.", firstNumber, secondNumber, firstNumber * secondNumber);
            Console.WriteLine("The result of dividing {0} by {1} is {2}.",
                firstNumber, secondNumber, firstNumber % secondNumber);
            Console.ReadKey();

        }
    }
}

I don't want to think of how much work it takes to make a book like this... it's crazy and I'm thankful for it... just learning something for the first time and getting not just right code or not explicit instructions are frustrating; I want sample code to simply work :( Why is it returning the "0" and not 1?

Old Pedant · September 8th, 2010, 06:28 PM

Ummm...either the book is wrong or you miscopied.

The division operator is *NOT* %

That is the *MODULO* operator. And 5 % 5 is indeed zero.

Try using / instead of %

(FWIW: "modulo" means "the remainder left over when doing an integer division". If you hark back to your elementary school days when you first learned division, you probably had problems where the teacher would ask you "What is the remainder when you divide 17 by 5?" The answer is of course 2. That is: 17/5 is 3 remainder 2. In virtually all computer languages, a "modulo" operator is available to do that for you. Indeed 17 % 5 ==>> 2.)

oldSqlNewToC · September 9th, 2010, 09:23 AM

LOL

The obvious worked ' / ' and does provide the division I was thinking of...

Thanks for explaining the ' % ' but after looking at wiki I still don't get its use but the wording in the book had my simple mind thinking it was talking about Ã·

Thank you :)