下面程序的功能是把文件file11.txt中重复字符去掉后（即若有多个字符相同，则只保留1个）写入文件file2.txt。请填空。Private Sub Command1__Click()Dim inchar AS String,temp AS String,outchar AS StringOutchar=” ”Open=”file1.txt” For Input AS #1Open=”file2.txt” For Output AS _________ n=LOF( _________ )inchar=Input$(n,1)For k=1 To ntemp=Mid(inchar,k,1)If InStr(outchar,temp)= _________ Thenoutchar=outchar & tempEnd IfNext kprint #2, _____________close #2close #1End Sub