Preparing for Battle

Introduction

In Old School Runescape, players purchase weapons and armor so they can gear up and defeat monsters across the land of Gielinor. Imagine you are a programmer working on the game and need to build a small tool that processes equipment purchase orders submitted by players. The tool will read purchase requests from a file and determine whether the purchase succeeds or fails based on the player’s available money.

If the purchase is successful, the transaction will be recorded. If there is an error in the data or the player cannot afford the item, the program will record the problem so it can be reviewed later.

In this assignment you will work with four famous gear types from Old School Runescape:

Name	Price
Scimitar	30000
Bow	200000
Armor	500000
Whip	2500000

Your program will read purchase orders in the following format:

Where:

• name is the name of the item the player wants to buy
• amount is how much money the player currently has
• type is the type of currency the player is using

There are two types of currency:

Name	Note
Gold	Standard Unit of Money
Platinum	Equivalent to 1000 gold pieces

For each order, your program must validate the input data and determine whether the player can afford the requested item. Valid purchases will be written to one output file, while errors will be written to another.

This assignment will help you practice several programming concepts used frequently in real software development:

• Working with input and output files

• Validating data read from files

• Using selection statements (if / else if / else)

• Handling input failures

• Producing structured program output

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Task

All files needed for this assignment can be downloaded here

Write a program that processes purchase orders from an input file and determines whether each order succeeds or fails. You will need to:

1. Open two output files:

   • purchases.txt which will contain successful purchases
   • errors.txt which will contain any errors encountered while processing the input file

2. Repeatedly prompt the user for an input filename until a valid file is entered. If an invalid file name is entered, output "Invalid filename\n" then read a new input file name until a valid one is entered.

3. Once a valid file is opened, read purchase orders from the file until the end of the file is reached.

4. For each line in the input file:

   a. Read the weapon name, amount of money, and type of currency. If the monetary amount cannot be read (input failure) output to errors.txt "line X error: Invalid monetary amount\n", where X is the line number where the error occurred. Then move on to the next line of input.

   b. Validate the type of currency. If the currency type is not gold or platinum output to errors.txt "line X error: Invalid monetary type\n", where X is the line number where the error occurred. Then move on to the next line of input.

   c. If the currency type is platinum, convert it to gold by multiplying the amount by 1000.

   d. Validate the weapon name. If the weapon name to purchase is not scimitar bow armor or whip output to errors.txt "line X error: Invalid weapon\n", where X is the line number where the error occurred. Then move on to the next line of input.

   e. If the weapon is valid, determine whether the player has enough gold to purchase the item. If the player does not have enough money, output to errors.txt "line X error: not enough T to buy a I\n", where X is the line number where the error occurred, T is the currency type read from the file (gold or platinum), and I is the item name the player is trying to buy. Then move on to the next line of input.

   f. If the player can afford the item first subtract the cost of the item from the player’s gold. Then, output to purchases.txt "purchasing I: A T remaining\n", where I is the item being purchased, A is the amount of money remaining after the purchase (if the player used platinum then the amount output should be divided by 1000), and T is the currency type for the purchase (gold/platinum). Then move on to the next line of input.

5. After all input has been processed, close the input and output files.

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Criteria for Success

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Example Program Interaction

An example of an interaction with your program is shown below. When interacted with, your program must produce the exact same results.

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as5_scimitars.txt

scimitar 30 platinum
scimitar 30000 gold

Terminal

AS5 % ./a.out
Filename: as5_scimitars.txt

purchases.txt

purchasing scimitar: 30 platinum remaining
purchasing scimitar: 30000 gold remaining

errors.txt

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as5_errors.txt

scimitar 29 platinum
scimitar 29999 gold
whip 2499 platinum
whip 2499999 gold
armor 499 platinum
armor 499999 gold
bow 199 platinum
bow 199999 gold
invalid 0 platinum
scimitar invalid platinum
scimitar 0 invalid

Terminal

AS5 % ./a.out
Filename: invalid
Invalid filename
Filename: data/as5_errors
Invalid filename
Filename: coding is hard
Invalid filename
Filename: as5_errors.txt

purchases.txt

errors.txt

line 1 error: not enough platinum to buy a scimitar
line 2 error: not enough gold to buy a scimitar
line 3 error: not enough platinum to buy a whip
line 4 error: not enough gold to buy a whip
line 5 error: not enough platinum to buy armor
line 6 error: not enough gold to buy armor
line 7 error: not enough platinum to buy a bow
line 8 error: not enough gold to buy a bow
line 9 error: Invalid weapon
line 10 error: Invalid monetary amount
line 11 error: Invalid monetary type

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as5_everything.txt

bow error platinum
whip 37367859 gold
armor 90124 platinum
scimitar 1500 gp
bow 299 platinum
platelegs 12 platinum
whip 1000 p
scimitar 834672 gold
armor invalid platinum
bow 9999 gold
scimitar 425635 gold
armor 500001 gold
whip 2500001 gold
helmet 1000 platinum
bow 947 platinum
armor 12 invalid
scimitar 342 platinum
whip 98735 platinum
armor 99999999 gold
bow 1000 platinum
scimitar inv platinum
whip 8178376 gold
boots 1500 gold
bow 1247345617 gold
scimitar 20 platinum
armor 0 gold
whip 3000 platinum
platinum 9999 gold
armor 3746 platinum
bow 52 platinumpieces
whip 100000 gold
scimitar 23627474 gold
armor 12 platinum
scimitar 30001 gold
bow 200 platinum
armor 758473 gold
whip 2501 platinum
scimitar 55 platinum
bow 327483948 gold
armor zero gold
cape 52 platinum
whip oops gold
armor 2375948 gold
bow 999999 gold
scimitar no gold
gloves 0 gold
whip 999999999 gold
scimitar 20 plat
armor 0 goldpieces
scimitar 9001 platinum
bow 52 platinum
whip err platinum
armor 501 platinum
platebody 100000 gold
whip 100000 g
scimitar 1500 gold
bow 9999 money
whip 1000 platinum
armor 900 platinum
scimitar 134 platinum
bow not gold
bow 8273648 gold
whip 154302 platinum
sword 20 platinum

Terminal

Filename: data/as5 
Invalid filename
Filename: data/as5_everything
Invalid filename
Filename: data/as5_everything.tx
Invalid filename
Filename: data/as5_everything.txt

purchases.txt

purchasing whip: 37367859 gold remaining
purchasing armor: 90124 platinum remaining
purchasing bow: 299 platinum remaining
purchasing scimitar: 834672 gold remaining
purchasing scimitar: 425635 gold remaining
purchasing armor: 500001 gold remaining
purchasing whip: 2500001 gold remaining
purchasing bow: 947 platinum remaining
purchasing scimitar: 342 platinum remaining
purchasing whip: 98735 platinum remaining
purchasing armor: 99999999 gold remaining
purchasing bow: 1000 platinum remaining
purchasing whip: 8178376 gold remaining
purchasing bow: 1247345617 gold remaining
purchasing whip: 3000 platinum remaining
purchasing armor: 3746 platinum remaining
purchasing scimitar: 23627474 gold remaining
purchasing scimitar: 30001 gold remaining
purchasing bow: 200 platinum remaining
purchasing armor: 758473 gold remaining
purchasing whip: 2501 platinum remaining
purchasing scimitar: 55 platinum remaining
purchasing bow: 327483948 gold remaining
purchasing armor: 2375948 gold remaining
purchasing bow: 999999 gold remaining
purchasing whip: 999999999 gold remaining
purchasing scimitar: 9001 platinum remaining
purchasing armor: 501 platinum remaining
purchasing armor: 900 platinum remaining
purchasing scimitar: 134 platinum remaining
purchasing bow: 8273648 gold remaining
purchasing whip: 154302 platinum remaining

errors.txt

line 1 error: Invalid monetary amount
line 4 error: Invalid monetary type
line 6 error: Invalid weapon
line 7 error: Invalid monetary type
line 9 error: Invalid monetary amount
line 10 error: not enough gold to buy a bow
line 14 error: Invalid weapon
line 16 error: Invalid monetary type
line 21 error: Invalid monetary amount
line 23 error: Invalid weapon
line 25 error: not enough platinum to buy a scimitar
line 26 error: not enough gold to buy armor
line 28 error: Invalid weapon
line 30 error: Invalid monetary type
line 31 error: not enough gold to buy a whip
line 33 error: not enough platinum to buy armor
line 40 error: Invalid monetary amount
line 41 error: Invalid weapon
line 42 error: Invalid monetary amount
line 45 error: Invalid monetary amount
line 46 error: Invalid weapon
line 48 error: Invalid monetary type
line 49 error: Invalid monetary type
line 51 error: not enough platinum to buy a bow
line 52 error: Invalid monetary amount
line 54 error: Invalid weapon
line 55 error: Invalid monetary type
line 56 error: not enough gold to buy a scimitar
line 57 error: Invalid monetary type
line 58 error: not enough platinum to buy a whip
line 61 error: Invalid monetary amount
line 64 error: Invalid weapon

See CodeGrade for more examples.

Note: The line breaks after the inputs in the example output formatting above are the ones placed into the terminal by the user hitting enter on their keyboard to input. CodeGrade does not enter values with a keyboard, but rather supplies input via Linux redirection to programs. So in CodeGrade's auto tests there will not be line breaks after the inputs.

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Submission Instructions

Save: Save your code as main.cpp. Do not ignore this step or save your file(s) with different names.

Submit: Your program source code must be submitted via CodeGrade as a properly named .cpp file prior to the deadline to receive full credit. Any submissions after the deadline will be subject to the class’ late policy.