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Exercise 1 It is required to evaluate an arithmetic expression that is represent

ID: 3536210 • Letter: E

Question

Exercise 1

It is required to evaluate an arithmetic expression that is represented in infix notation. Develop a program such that the arithmetic expression in infix notation is first converted to postfix notation and then uses postfix notation to evaluate the expression.

Note: You are required to use suitable data structures that you have studied to convert to postfix notation and then evaluate it.

Example:

Infix notation: A * B + ( C – D / E)

Postfix notation: AB*CDE/-+

Assume test values A = 8, B= 6, C = 8, D= 6 and E = 2 and print the result.

Hints:

By a program

Infix

Stack

Postfix

A * B + (C - D / E)

Empty

* B + (C - D / E)

Empty

A

B + (C - D / E)

*

A

+ (C - D / E)

*

AB

(C - D / E)

+

AB*

C - D / E)

(+

AB*

- D / E)

(+

AB*C

D / E)

-(+

AB*C

/ E)

-(+

AB*CD

E)

/-(+

AB*CD

)

/-(+

AB*CDE

+

AB*CDE/-

AB*CDE/-+

Note: To simplify your task, just consider the priorities as given below.

Multiplication and division operators have equal priorities but have higher priorities than addition and subtraction operators. Addition and subtraction operators have equal priorities.


Exercise 2

You have been provided with input.txt file. It is required to list all the unique words that are present in the input.txt file and the number of occurrences of each unique word. It must also be possible to print the number of occurrences of a given unique word that is input by the user.

Develop a program using the data structure/ data structures that you feel is/are most suitable for the above mentioned requirements and test it.

Note: You can make the following assumptions

Sample Input/Output:

Input.txt:

The expression exp1 && exp2 is true if and only if exp1 == true and exp2 == true

Unique words and their occurrences:

word

Occurs

The

expression

exp1

exp2

&&

is

true

if

and

only

==

1

1

2

2

1

1

3

2

1

1

2

Input the word: true

true occurs 3 times.

Infix

Stack

Postfix

A * B + (C - D / E)

Empty

* B + (C - D / E)

Empty

A

B + (C - D / E)

*

A

+ (C - D / E)

*

AB

(C - D / E)

+

AB*

C - D / E)

(+

AB*

- D / E)

(+

AB*C

D / E)

-(+

AB*C

/ E)

-(+

AB*CD

E)

/-(+

AB*CD

)

/-(+

AB*CDE

+

AB*CDE/-

AB*CDE/-+

Explanation / Answer

here is your answer

http://www.mec.ac.in/resources/notes/notes/ds/postfix.htm