Unknown Identifier 'i'

Question

I was scripting a gamescript and following the instructions of a beginner's guide to Unity, until I ran into a problem to which I cannot find a fix for.

 for(i=0; i<rows; i++)

I will post the entire code if needed.

 var cols:int = 4;
 var rows:int = 4;
 var totalCards:int = cols*rows;
 var matchesNeededToWin:int = totalCards * 0.5;
 var matchesMade:int = 0;
 var cardW:int = 100;
 var cardH:int = 100;
 var aCards:Array;
 var aGrid:Array;
 var aCardsFlipped:ArrayList;
 var playerCanClick:boolean;
 var playerHasWon:boolean = false;
 
 function Start () {
     playerCanClick = true; // We should let the player play, don't you think? XD
     
     //Initialize the arrays as empty lists:
     aCards = new Array();
     aGrid = new Array();
     aCardsFlipped = new ArrayList();
     
     for(i=0; i<rows; i++)
     {
      aGrid[i] = new Array(); // Create a new, empty array at index i
      
      for(j=0; j<cols; j++)
      {
       aGrid[i][j] = new Card();
      }
     }
 
 }
 
 
 function Update () {
 
 }
 
 class Card extends System.Object
 {
     var isFaceUp:boolean = false;
     var isMatched:boolean = false;
     var img:String;
     
     function Card()
     {
         img = "robot";
     }
 }
 
 function OnGUI()
 {
     GUILayout.BeginArea (Rect (0, 0, Screen.width, Screen.height));
     BuildGrid();
     GUILayout.EndArea();
     print("Building grid!");
 }
 
 function BuildGrid()
 {
     GUILayout.BeginVertical();
     for(i=0; i<rows; i++)
     {
         GUILayout.BeginHorizontal();
         for(j=0; j<cols; j++)
         {
             var card:Object = aGrid[i][j];
             if(GUILayout.Button(Resources.Load(card.img),
             GUILayout.Width(cardW)))
             {
                 Debug.Log(card.img);
             }
         }
         GUILayout.EndHorizontal();
     }
     GUILayout.EndVertical();
 }

Answer 1

Answer by robertbu · Jun 11, 2013 at 06:04 AM

It should be:

 for(var i=0; i<rows; i++)

Or if you need 'i' to live beyond the for() statement you can do:

 var i : int;
 for(i=0; i<rows; i++)

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Answer 2

Answer by bubzy · Jun 11, 2013 at 06:05 AM

I don't know javascript but in c# you have to declare the variable BEFORE you start the loop so:

 for(int i=0; =<rows; i++)
 {
 ////blah
 }

or (as fafase correctly stated)

 int i = 0;
 
 for (i=0;i<rows;i++)
 {
 //blah
 }

without the int declaration, the program doesn't know what 'i' is. maybe you have to

 var i

or something

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fafase · Jun 11, 2013 at 06:13 AM 2

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That is not true. In C# you can do:

 int i = 0;
 for( ; i < Something; i++){}

Or even reuse the same variable for two loops:

 int i = 0;
 for( ; i < Something; i++){}
 // I continue with the value of i left from the previous loop
 for( ; i < Something+100; i++){}

Finally, var does work in C# as long as you provide a value that allows the compiler to infer the type.

 var fl = 0.5f; // Same as float fl = 0.5f
 var str = "A string"; // Same as string str = "A string";

Unknown Identifier 'i'

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