Array index is out of range?

Hi there

I am beginning a terrain editor and have just started trying to make a diamond square algorithm script. I am currently having an issue with my code where it says array index is out of range. I have spent days trying to solve this issue and would appreciate help.

 #pragma strict
     var width : int;
     var height : int;
     var desiredHeight : float;
     var step: int;
 function Start () {
     var terrain = GetComponent(Terrain);
     width = terrain.terrainData.heightmapWidth -1;
     height = terrain.terrainData.heightmapHeight -1;
     step = width;
     
     var heights = terrain.terrainData.GetHeights(0,0,width,height);
     
     for( var j=0; j<width; j = j + step)
         for( var i=0; i<width; i = i + step)
         print(j);
         print(i);
         heights[j,i] = .1;
         terrain.terrainData.SetHeights(0,0,heights);
 }

EDIT

Managed to sort the Array index is out of range problem. However i'm only getting a elevated part at 64,64. Any ideas New code

 #pragma strict
     var width : int;
     var height : int;
     var desiredHeight : float;
     var step: int;
 function Start () {
     var terrain = GetComponent(Terrain);
     width = terrain.terrainData.heightmapWidth;
     height = terrain.terrainData.heightmapHeight;
     
     
     var heights = terrain.terrainData.GetHeights(0,0,width,height);
 
     width = width-1;
     height = height-1;
     step = width;
     for( var j=0; j<width; j = j + step)
         for( var i=0; i<width; i = i + step)
         print(j);
         print(i);
         heights[i,j] = .1;
         terrain.terrainData.SetHeights(0,0,heights);
 }