Net 13

CBSE NET JUNE 2014 PAPER III

The reverse polish notation equivalent to the infix expression 
((A + B) * C + D) / (E + F + G) is

(A) A B + C * D + E F + G + / 
(B) A B + C D * + E F + G + / 
(C) A B + C * D + E F G + +/ 
(D) A B + C * D + E + F G + / 

Ans:-A

Explanation:-

Always the expression given within parenthesis is converted first. Since there are 2 expressions with the parenthesis, I am going with the expression (E + F + G) first, the order does not matter. 

In the expression (E + F + G), there are 3 operands E,F and G and two operators, both being +. Since both the operators are the same, the expression is going to be evaluated from left to right. So E + F is considered first and converted into postfix form which is EF+. So, the expression becomes, 

( ( A + B ) * C + D) / ([E F +] + G)

Any expression converted into postfix form is going to be written in square brackets. 

( ( A + B ) * C + D) / [ E F + G + ] 
. Here EF+ is one operand, G is another operand and + is the operator. 

The next expression to be converted into postfix is ( A + B).

[ A B + ] * C + D) / [ E F + G + ]

Now, the expression which is enclosed in parenthesis is evaluated and so, we get

[ [ A B + ] C * ] + D) / [ E F + G + ]

[ A B + C * D + ] [ E F + G + ]

[ A B + C * D + ] [ E F + G + ] / 

Answer is, final postfix expression A B + C * D + E F + G + /.

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