The names 'array1' and 'getnum' do not exist in the current context

Question


class Program {
    static void Main(string[] args) {
        string getnums = Console.ReadLine();
        int getnum=Convert.ToInt32(getnums);
        int[] array1=new int[getnum];
        
        GenerateNum(getnum);
        RevArray();
        PrintArray();
    }
    static int[] GenerateNum(int g){
        
        for(int index=0; index<g; index++){
            array1[index]=index;
        }
        return array1;
    }
    static int[] RevArray(){
        for(int index=0; index<=getnum/2; index++){
            int a=array1[index];
            array1[index]=array1[getnum];
            array1[getnum]=a;
        }
        return array1;
    }
    static void PrintArray(){
        Console.WriteLine(array1);
    }
}

Hi. I'm trying to write a program with three methods and each of them does one action. GenerateNum() takes getnum as a parameter and creates an array with numbers up to getnum. RevArray() reverses the array and PrintArray() prints it out. However I get error messages. All of them are name 'array1' and name 'getnum' does not exist in the current context. I have defined them in the Main method, then why doesn't it work? Please help me. Thanks in advance!

Those variables are local to the `Main` function so you can't access them. You need to declare them in a wider scope (Like defining them as fields of `Program` class). — Eldar, Dec 16 '20 at 09:09

Heinzi · Accepted Answer · 2020-12-16T09:18:04.237

I have defined them in the Main method

Variables defined in some method A are only available to that method. If you want to use them in other methods, you need to either

declare them in a wider scope (for example, by making them static fields of your class) or by
passing them as parameters.

The latter is usually preferable (see, e.g. Are global variables bad?).

For example, GenerateNum could be defined as

 static int[] GenerateNum(int g, int[] array1) { ... }

and called as

GenerateNum(getnum, array1);

There are lots of other things that could be improved in your code (for example, you do not need to return arrays if you modify them in-place, and GenerateNum could allocate the array itself instead of requiring an array with the correct size to be passed), so you might want to submit your code to https://codereview.stackexchange.com after you got it running.

The names 'array1' and 'getnum' do not exist in the current context

1 Answers1