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fighter
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Index was outside the bounds of the array.

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Hi all, i'm new to C#, and as i try to debug the following code, i take the error : "Index was outside the bounds of the array. " in line : Console.WriteLine(args[0]); . The source code is the following:

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

namespace Password
{
class Password
{
static void Main(String[] args)
{

Console.Write("Type your password");
Console.WriteLine(" ");
Console.WriteLine(args[0]);
if (args[0].StartsWith("JAVA"))
Console.WriteLine ("Ok, You have typed the correct" + "Password");
else
Console.WriteLine("ERROR!");
Console.ReadLine();
}


}

}

I cannot fix this. Since i declare [0] size of args, what is the problem ?? Thanks in advance guys

error index array
  • asked one year ago
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last answered one year ago

2 answers

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tick
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If you pass any arguments to your program when you run it from the command line, then these arguments are stored in the 'args' array. I'd imagine you're not doing this and so 'args' will be empty.

If you want the user to input a password which you then check for correctness, I'd store it in a string variable. Something like this:

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

namespace Password
{
   class Password
   {
      static void Main(String[] args)
      {
          Console.Write("Type your password : "); 
          string password = Console.ReadLine(); 
          if (password.StartsWith("JAVA"))
             Console.WriteLine ("Ok, You have typed the correct password");
          else
             Console.WriteLine("ERROR!"); 
          Console.ReadLine();
      }
   }
}

  • answered one year ago by:

    vulpes
    17279
(x)
fighter
3

Thanks a lot! This is what i was trying to do in order to fix this error, but the source code i published is an example for amateurs from a book chapter and i tried to run it. Probably he is wrong.. If i declare an array "args[]" and declare its size, would it run ?

(x)
vulpes
17279

Well, the compiler wouldn't let you declare another array called 'args' in the Main() method because it would conflict with the parameter of the same name. If the user were passing the password when invoking the program (rather than being asked for it when the program starts), then args[0] would automatically contain the password. Perhaps this is where the confusion lies?

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The args[] array contains command line parameters as vulpes said. If none are passed, that array has a size of 0 entries. Since arrays start with indexes at 0, 0 is actually the first item. There is no first item in a list of 0 items, hence your error message.

Once you get more advanced, you can do something like this to actually check for command line arguments:

if (args.Length == 0) { Console.WriteLine("No command line arguments were passed!"); }


fm

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