appending to a string array in C#

Question

 string Input = "";
 string[] Words = { "elephant", "lion" };
 string[] Clues = { "Has trunk?", "Is gray?", "Is yellow?", "Has mane?"};

.........

 Console.WriteLine("Do you want to add you own animal? y/n ? \n");
 Input = Console.ReadLine();
 if (Input == "Y" || Input == "y")
 {
 Console.WriteLine("Enter an animal name: \n");
 //Array.Resize(ref Words, Words.Length + 1);
 Input = Console.ReadLine();
 Words[Words.Length] = Input;
 Console.WriteLine("Enter 2 clues \n");
 for (int i = 1; i <=2 ; i++)
 {
 Console.WriteLine("Clue" + i + ":");
 Clues[Clues.Length] = Console.ReadLine();
 }
 }

This is the standard guess the animal game.. I am getting an index out of bounds at line Words[Words.Length] = Input;.. the new animal and clues entered also needs to be available the next time i play the game..

• mjwills: Use List<string> (and VariableName.Add) rather than an array.
• mjwills: Possible duplicate of How to properly save application data for later use
• mjwills: Also, arrays in C# are 0-based, not 1-based. So for (int i = 1; i <=2 ; i++) should be for (int i = 0; i < 2 ; i++).

Answer 1

Instead string [] use List<T> from System.Collections.Generic

And you can use Add method to add new value like this.

Console.WriteLine("Enter an animal name: \n");
Input = Console.ReadLine();
Words.Add(Input);

And if want an array at the end, you can use ToArray method. Like this.

Words.ToArray();

Answer 2

You can use List<string> instead of Array. Your code throw exception because you are trying to add element to an Array in outranged index. I modified your code like this;

 string Input = "";
 var Words = new List<string> { "elephant", "lion" };
 var Clues = new List<string> { "Has trunk?", "Is gray?", "Is yellow?", "Has mane?" };
 Console.WriteLine("Do you want to add you own animal? y/n ? \n");
 Input = Console.ReadLine();
 if (Input == "Y" || Input == "y")
 {
 Console.WriteLine("Enter an animal name: \n");
 //Array.Resize(ref Words, Words.Length + 1);
 Input = Console.ReadLine();
 Words.Add(Input);
 Console.WriteLine("Enter 2 clues \n");
 for (int i = 1; i <= 2; i++)
 {
 Console.WriteLine("Clue" + i + ":");
 var clueInput = Console.ReadLine();
 Clues.Add(clueInput);
 }
 }

Answer 3

Adding a string to a finite array such as the one you have declared causes this additional item to be beyond the bounds of this array, ie. you are squeezing more things into a space that cannot hold that amount. Once created (at compilation) this size is fixed and can't be changed until next time.

I think what you are looking for are lists List<string> that use list.Add() to easily manipulate content dynamically during runtime.

Let me know if that answers your question or if you require more details.

Answer 4

why don't you use List rather Array.

 string Input = "";
 List<string> Words = new List<string>(){ "elephant", "lion" };
 List<string> Clues =new List<string>() { "Has trunk?", "Is gray?", "Is yellow?", "Has mane?"};
 Console.WriteLine("Do you want to add you own animal? y/n ? \n");
 Input = Console.ReadLine();
 if (Input.toLower() == "y")
 {
 Console.WriteLine("Enter an animal name: \n");
 //Array.Resize(ref Words, Words.Length + 1);
 Input = Console.ReadLine();
 Words.Add(Input);
 Console.WriteLine("Enter 2 clues \n");
 for (int i = 1; i <=2 ; i++)
 {
 Console.WriteLine("Clue" + i + ":");
 Clues.Add(Console.ReadLine());
 }
 }

please follow this.

Answer 5

`Console.WriteLine("Enter an animal name: \n");
//Hear Words length is 2 and Data (0 = elephant,1 = lion)
Array.Resize(ref Words, Words.Length + 1);
//Hear Words length is 3 and Data (0 = elephant,1 = lion,2 = null)
Input = Console.ReadLine();
//if you write Words[Words.Length] means you tried to access 3 index which is not available.
//You should write this.
Words[Words.Length - 1] = Input;`