[Closed] what are flags and mask flags in editablepoly

i went through that several time in max script help and didnt get it well could anybody tell me what is flag and maskflags there s explaination code in the help i dont get it all

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[left]theObj = plane isSelected:true
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 [left]convertto theObj editable_poly
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 [left]nVerts = theObj.numverts
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 [left]bit30 = bit.set 0 30 true
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 [left]bit31 = bit.set 0 31 true
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 [left]bit32 = bit.set 0 32 true
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 [left]-- set a bit on first 3/4 or so verts
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 [left](
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 [left]flagsToSet = bit30
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 [left]flagsToMask = 0
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 [left]vertexSet = #{1..(3*nVerts/4)}
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 [left]theObj.setVertexFlags vertexSet flagsToSet flagMask:flagsToMask  generateUndoRecord:true
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 [left]ok
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 [left]-- and another on middle block
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 [left]flagsToSet = bit31
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 [left]flagsToMask = 0
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 [left]vertexSet = #{(nVerts/3)..(nVerts-4)}
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 [left]theObj.setVertexFlags vertexSet flagsToSet flagMask:flagsToMask  generateUndoRecord:true
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 [left]ok
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 [left]-- set a bit on last 2 verts
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 [left]flagsToSet = bit32
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 [left]flagsToMask = 0
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 [left]vertexSet = #{(nVerts-2)..nVerts}
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 [left]theObj.setVertexFlags vertexSet flagsToSet flagMask:flagsToMask  generateUndoRecord:true
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 [left]ok
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 [left]-- get verts with bit30, 31, 32 set
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 [left]format "30: %
" (polyOp.getVertsByFlag theObj bit30)
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 [left]format "31: %
" (polyOp.getVertsByFlag theObj bit31)
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 [left]format "32: %
" (polyOp.getVertsByFlag theObj bit32)
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 [left] 
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 [left]-- get verts with bit30 set, but not bit31
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 [left]format "30 and !31: %
"  (polyOp.getVertsByFlag theObj bit30 mask:(bit30+bit31))
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 [left]-- get verts with bit31 not set, doesn't matter what the <flag>  
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 [left]-- value is as long as it's not bit31
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 [left]format "!31: %
"  (polyOp.getVertsByFlag theObj bit30 mask:(bit31))
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 [left]-- get verts with bit30 and bit31 set
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 [left]format "30 and 31: %
"  (polyOp.getVertsByFlag theObj (bit30+bit31))
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 [left]-- get verts with neither bit31 or bit32 set, doesn't matter what  
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 [left]-- the <flag> value is as long as it's not bit31 or  bit32
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 [left]format "!(31 or 32): %
"  (polyOp.getVertsByFlag theObj bit30 mask:(bit31+bit32))
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so can i have any clue explaination for that?