Reference no: EM132211182
Write a program that will populate a queue with post-fix (reverse polish) integer expressions and then print out the solution to each expression.
A stack is used to calculate values in post-fix notation. Numbers are pushed onto the stack, and when an operator is reached it pops off the last two numbers and then pushes the resulting value back on the stack.
This program must:
Assume that each number and operator is separated by any type of space, and each expression is separated by a new line
Calculate values using the algorithm mentioned above and in the slides for addition, subtraction, multiplication, and division (+,-,*,/)
Error message if the user tries to divide by zero
Read a given file
Make sure to check if there's at least two items on the stack before when an operator is encountered or else it's not a properly formatted post-fix expression
Finish when the program reaches the end of the string and it has only one value left on the stack, then that value is popped off and returned. Otherwise it was not properly formatted
Use your own created stack and queue, and not java's built in stack and queue
You may use any implementation so either an array or a linked structure.
HINTS! First when you're processing the inputted string you can use a Scanner and call the method next() to get each token. From there you can evaluate if that token is an operator, numeric value, or an error.
If it's a numeric value then you may parse that string using Integer.parseInt() to get the integer value. You may also call Integer.parseInt() in a try-catch block. If the token is not an integer an exception will be raised and should be immediately halted.
Example Dialog:
Welcome to the reverse Polish Calculator!
Enter in the name of the file
revPol.txt
Calculating 3 2 +
Result is 5
Calculating 5 1 2 + 4 * + 3 -
Result is 14
Calculating 2 3 4 +
Ill formatted expression
Result is 0
Calculating 0
Result is 0
Calculating 6 7 8 9 * + - 8 4 / /
Result is -36
Calculating 1 2 3 4 + - 5 6 * + +
Result is 26
Calculating 2 4 + 5 + 7 + 8 + 9 +
Result is 35
Calculating +
Ill formatted expression
Result is 0
Calculating 2 b +
Exception! For input string: "b"
Result is 0
Calculating 1 0 /
Cannot divide by 0
Result is 0
Please provide a solution that does not use buffered reader.