for AND and OR operation
else if ( s . length == 5 ) { let a = s [ 0 ] . charCodeAt ( 0 ) - 48 , b = s [ 4 ] . charCodeAt ( 0 ) - 48 , c ; if ( s [ 2 ] == ' ' ) { c = a & b ; } else { c = a | b ; } arr . push ( String . fromCharCode ( c + 48 ) ) ; } } else { arr . push ( str [ i ] ) ; } } return arr [ arr . length - 1 ] ; }