maze problem notes in classical experimentation in psychologya rat is placed through the door of large box in which walls are set up to restrict movements in most directions the rat' movement is observed as it finds outthrough the obstaclesa way to escape from the box two-dimensional version of this problem is easy to formulate where rectangular maze is conceived as consisting of number of unit square rooms such that movement from one square to another is restricted an by maze can be represented by an array maze of size [ nwhere each maze[ ,jrepresents unit room if maze[ ,jis the room may be entered into but it cannot be entered if maze[ ,jis the entrance is at maze[ , and the exit is at maze[ ,nevaluation of expressions one of the biggest technical hurdles faced when conceiving the idea of higher level programming languagesis to generate machine language instructionswhich would properly evaluate any arithmetic expression complex assignment statement such asz - might have several meaningseven if it were uniquely definedby the full use of parenthesis an expression is made up of operandsoperators and delimiters the above expression has five operands xyab and the first problem with understanding the meaning of an expression is to decide in what order the operations are carried out this means that every language must uniquely define such an order to fix the order of evaluation we assign to each operator priority set of sample priorities are as followsoperator (or **unary -unary+![not*/+>=!&|||priority associativity left to right right to left left to right left to right left to right left to right left to right left to right but by using parenthesis we can override these rules and such expressions are always evaluated with the inner most parenthesized expression first the above notation of any expression is called infix notation (in which operators come in between the operandsthe notation is traditional notationwhich needs operator' priorities and associativities but how can compiler accept such an expression and produce correct polish notation or prefix form (in which operators come before operandspolish notation has several advantages over infix notation such asthere is no need for considering priorities while evaluating themthere is no need of introducing parenthesis for maintaining order of execution of operators similarlyreverse polish notation or postfix form also has same advantages over infix notationin this notation operators come after the operands consider the following examples infix prefix postfix + +xy xyx+ * + +yz xyz* + - -+xyz xyz*+lovely professional university