HW6: Chapter 4
Ex 4.5
Using the technique suggested here, where natural language descriptions are presented in a standard format, write plausible user requirements for the following functions:
1. An unattended petrol (gas) pump system that includes a credit card reader. The customer swipes the card through the reader, then specifies the amount of fuel required. The fuel is delivered and the customer’s account debited.
Function: Give gas to customer, accept and charge the customer's credit card, and print a receipt.
Description: The customer swipes the card through the reader, then specifies the amount of fuel required. The fuel is delivered and the customer’s account debited.
Inputs: Amount of gas that the customer wants and the customer's credit card information
Source: credit card machine/reader and either screen where the amount of gas the customer wants is inputted or i guess the amount of gas is determined when the customer re-racks the gas nozzle.
Outputs: amount of gas requested by customer, and a receipt, and the price of the gas taken from the credit card.
Destination: the gas goes into the customer's gas tank and the price is deducted from the customer's credit card account
Action: Customer pulls up to gas station pump, selects the amount of gas they would like, system calculates the price, customer swipes his/her credit card and pays the amount, and then they pump the gas into their card, they re-rack the gas pump and take their receipt
Requires: price of gas, a customer
Precondition: pump must be on and card reader is ready, the pump must know the price of gas for that day, and the credit card must work and not be declined.
Postcondition: the correct amount of fuel is pumped, and the correct amount of money is charged to the card
The cash-dispensing function in a bank ATM.
Function: dispense the amount of cash that is requested to the customer and remove that amount of cash from their bank account
Description: Customer comes to an ATM and inserts their card. The customer request an amount of money they would like to withdrawal from their account. That amount is given to them in cash and the same amount is removed from their bank account
Inputs: customer's credit card information
Source: credit card reader
Outputs: cash and receipt
Destination: customer's wallet
Action: Customer comes to an ATM and inserts their card. The customer request an amount of money they would like to withdrawal from their account. That amount is given to them in cash and the same amount is removed from their bank account
Requires: the amount of cash in the ATM
Precondition: the customer has the same or more amount of money in their account than they request to withdrawal, the amount of money that is supposed to be withdrew is less than the amount of cash in the ATM, the customer's credit card works properly and is not declined
Postcondition: the ATM dispenses the correct amount of cash and removes the same correct amount of cash from the customer's bank account and a receipt is printed
In an Internet banking system, a facility that allows customers to transfer funds from one account held with the bank to another account with the same bank.
Function: Transfer money from one bank account to another bank account with the same bank
Description: a facility that allows customers to transfer funds from one account held with the bank to another account with the same bank.
Inputs: Bank account information of both bank accounts, amount to transfer
Source: user input
Outputs: money successfully transferred from one account to another, and confirmation of transfer
Destination: Other bank account
Action: Customer signs on to the internet banking system, they enter the information of the account they wish to transfer funds to. They select the amount of money they wish to transfer and then they receive a confirmation once the transfer is complete
Requires: customer's account information, and the account info of the account they wish to transfer funds to
Precondition: Customer's must have the same or more money in their account than the amount of money they wish to transfer. both accounts must be at the same bank
Postcondition: the correct amount of funds is deducted from the first account that is added to the second account
Ex 4.6.
Suggest how an engineer responsible for drawing up a system requirements specification might keep track of the relationships between functional and non-functional requirements.
If an engineer separates the system requirements into two groups: Functional and non-functional. This will make it easier for the engineer to keep track of requirements and they won't have to distinguish between non-functional and functional during the process. With the two lists, they can also prioritize what needs to be completed first or what needs to get completed before moving on to another requirement
Ex 4.7.
Using your knowledge of how an ATM is used, develop a set of use cases that could serve as a basis for understanding the requirements for an ATM system.
1. Customer inserts credit card.
2. Customer enters correct PIN
3. Customer enters invalid PIN
4. Customer wants to deposit money
5. Customer wants to check funds
6. Customer wants to make a withdrawal
7. Customer wants to transfer funds
8. Customer wants a receipt
9. Customer does not want a receipt
Using the technique suggested here, where natural language descriptions are presented in a standard format, write plausible user requirements for the following functions:
1. An unattended petrol (gas) pump system that includes a credit card reader. The customer swipes the card through the reader, then specifies the amount of fuel required. The fuel is delivered and the customer’s account debited.
Function: Give gas to customer, accept and charge the customer's credit card, and print a receipt.
Description: The customer swipes the card through the reader, then specifies the amount of fuel required. The fuel is delivered and the customer’s account debited.
Inputs: Amount of gas that the customer wants and the customer's credit card information
Source: credit card machine/reader and either screen where the amount of gas the customer wants is inputted or i guess the amount of gas is determined when the customer re-racks the gas nozzle.
Outputs: amount of gas requested by customer, and a receipt, and the price of the gas taken from the credit card.
Destination: the gas goes into the customer's gas tank and the price is deducted from the customer's credit card account
Action: Customer pulls up to gas station pump, selects the amount of gas they would like, system calculates the price, customer swipes his/her credit card and pays the amount, and then they pump the gas into their card, they re-rack the gas pump and take their receipt
Requires: price of gas, a customer
Precondition: pump must be on and card reader is ready, the pump must know the price of gas for that day, and the credit card must work and not be declined.
Postcondition: the correct amount of fuel is pumped, and the correct amount of money is charged to the card
The cash-dispensing function in a bank ATM.
Function: dispense the amount of cash that is requested to the customer and remove that amount of cash from their bank account
Description: Customer comes to an ATM and inserts their card. The customer request an amount of money they would like to withdrawal from their account. That amount is given to them in cash and the same amount is removed from their bank account
Inputs: customer's credit card information
Source: credit card reader
Outputs: cash and receipt
Destination: customer's wallet
Action: Customer comes to an ATM and inserts their card. The customer request an amount of money they would like to withdrawal from their account. That amount is given to them in cash and the same amount is removed from their bank account
Requires: the amount of cash in the ATM
Precondition: the customer has the same or more amount of money in their account than they request to withdrawal, the amount of money that is supposed to be withdrew is less than the amount of cash in the ATM, the customer's credit card works properly and is not declined
Postcondition: the ATM dispenses the correct amount of cash and removes the same correct amount of cash from the customer's bank account and a receipt is printed
In an Internet banking system, a facility that allows customers to transfer funds from one account held with the bank to another account with the same bank.
Function: Transfer money from one bank account to another bank account with the same bank
Description: a facility that allows customers to transfer funds from one account held with the bank to another account with the same bank.
Inputs: Bank account information of both bank accounts, amount to transfer
Source: user input
Outputs: money successfully transferred from one account to another, and confirmation of transfer
Destination: Other bank account
Action: Customer signs on to the internet banking system, they enter the information of the account they wish to transfer funds to. They select the amount of money they wish to transfer and then they receive a confirmation once the transfer is complete
Requires: customer's account information, and the account info of the account they wish to transfer funds to
Precondition: Customer's must have the same or more money in their account than the amount of money they wish to transfer. both accounts must be at the same bank
Postcondition: the correct amount of funds is deducted from the first account that is added to the second account
Ex 4.6.
Suggest how an engineer responsible for drawing up a system requirements specification might keep track of the relationships between functional and non-functional requirements.
If an engineer separates the system requirements into two groups: Functional and non-functional. This will make it easier for the engineer to keep track of requirements and they won't have to distinguish between non-functional and functional during the process. With the two lists, they can also prioritize what needs to be completed first or what needs to get completed before moving on to another requirement
Ex 4.7.
Using your knowledge of how an ATM is used, develop a set of use cases that could serve as a basis for understanding the requirements for an ATM system.
1. Customer inserts credit card.
2. Customer enters correct PIN
3. Customer enters invalid PIN
4. Customer wants to deposit money
5. Customer wants to check funds
6. Customer wants to make a withdrawal
7. Customer wants to transfer funds
8. Customer wants a receipt
9. Customer does not want a receipt
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