CS 2433 RPN P6

Problem: Write a program, named p6.cpp that behaves in the manner describe in programming assignment 5, but which incorporates the changes listed below. As this is the first C++ program, the required changes involve transitioning from C-style I/O to C++ I/O mechanisms.

• Change the implementation of the stack to use a container, specifically the vector container.
  • For the pop operation stack this will require extracting the value of the stack top before calling the pop_back method of the vector , since pop_back does not return that value, merely removing that entry from the vector .
  • The push operation on the stack you may use the push_back method to add the item being pushed onto the stack, but it is recommended that this be done in your program's push function, as you need to allow for potential changes to the implementation in the future.
  • The size of your stack's vector may be used to determine the stack size when detecting possible stack underflows. Due to the ability of a vector to grow as required, stack overflows remain a practical impossibility, just as when using malloc to allocate nodes for use in managing the stack.
• Add an operator named peek , which causes the program to write the current stack top to cout , without removing the value from the stack.
• Add an alternate version of peek which will have the format 'peek("< test_to_print>")', which causes the value displayed to be shown following the text specified.
• Add an operator named dump that causes the string "Stack Contents:\n" followed by the stack contents, one element per line, or, if the stack is empty, "Stack empty.\n"

Naming: Your submitted file is to be named p6.cpp. This will be the last pure C program of the semester.

Output: Output requirements are unchanged from programming assignment 4, in the sense that what is displayed is not changed, even though the method of output is required to follow C++ conventions using C++ objects and libraries. Thus, the following output requirements are unchanged.

Your program's normal output must be to stdout and of one of the formats following, assuming argc and argv are the usual parameters for main() and where < program_name> is argv[0] .

If argv[1] is "--help" display the following.

Usage: < program_name>

"< program_name> -- help"
display thi i s usage material. .

"< program_name> -rpn"
The program accepts input from standard input as a sequence
of numbers and operators. The numbers (operands, as
integers or floating point numbers) read are push ed on a
stack until needed. When an operator is read, the required
operands are popped from the stack and used to perform the
calculation, with the result placed on the stack. Valid
operators are +, -, * and /, are interpret ed as addition,
subtraction, multiplication and division, respectively, as
described below. An additional operator is =, which
indicates that the value at the top of the stack is popped
from th e stack and displayed along with the number of
values remaining on the stack, whereupon the program
terminates.

Stack underflows generate an error message and halt the
program, as do a stack overflows. Unrecognized input
tokens produce error messages and result in program
termination, as do unrecognized command line arguments.
The size of the stack is 10.

Stack operations are performed so as to produce results
identically as indicated here.

+ : push(pop() + pop());
- : temp = pop(); push(pop() – – temp;
* : push(pop() * pop());
/ : temp = pop(); push(pop() / temp;
' : push(1.0 / pop());
~ : push(-pop());
** : temp = pop(); push(pow(pop(),temp));
swap : t1 = pop(); t2 = pop(); push(t1); push(t2);
copy : temp = pop(); push(temp); push(temp);
= : pop stack top and display it as the result with the number of stack element s remaining.
dump : display the contents of the calculat or stack.
peek : display the top-of-stack value.
peek("< text>") : display the top-of-stack value following the specified text.

The above describes the majority of the behavior of the program you are to write. To reiterate and expand important points:

• If the first command-line argument is "--help" subsequent command-line arguments are ignored, the usage message is displayed and the program terminates.
• If the first command-line argument is "-rpn", subsequent command line arguments are ignored and the program proceeds with reading from standard input.
• Invalid/unrecognized command-line arguments produce a suitable error message, display the usage information above, and terminate the program.
• If an unrecognized token is read from standard input, a suitable error message for the type of error is to be displayed with the usage text and the program terminated.
• A malformed peek() operand is an error, and should be reported as such, and in the same manner as other error messages.
• If all inputs are recognized and no errors arise, print the following to stdout.

Result = < result popped from top of stack>.
< number of operands on the stack> values remain on the stack.

For all error conditions, print the required output to stderr.

Remember that any item delimited by angle brackets ("< >") is to be replaced with the appropriate information, without the angle brackets.