Problem definition and feasibility study
1, why should conduct a feasibility study in the early stages of software development? Feasibility study should target from what?
(1) the development of a software, you need to determine the original system model and is a realistic goal, after the completion of the system can bring benefits worth the investment if large degree of development of this system, in order to prevent a waste to spend any time on the project , manpower, hardware and software resources and funding, it is necessary to conduct a feasibility study. The essence of the feasibility study is to conduct a compression greatly simplifies the system. The analysis and design, system analysis is carried out at a higher level in a more abstract way and design process. The purpose of the feasibility study is to determine the problem with minimum cost in the shortest possible time is able to solve.
(2) study the feasibility of the following three aspects:
? A, technical feasibility, using existing technology enables the system do
B, economic feasibility, the economic benefits of this system can exceed its costs to develop it?
C, operational feasibility, the way the system works within the user's organization do?
2. To facilitate the depositors, a bank savings to be developed computer system. Depositors deposit slip filled out by the clerk or teller single type system, if the deposit, the deposit system records the name, address, type of deposit, deposit date, interest rate and other information, and print deposit slips to depositors; if it is withdrawal, the system calculates interest and print list of interest to depositors. Please write the definition of the problem and analyze the feasibility of this system.
First, the problem definition
(1) If the deposits, depositors fill out a deposit slip, then handed the clerk type system, while the system also records the deposit's name, address (or phone number), ID number, the type of deposit, deposit date, information on interest rates, after the completion of the printing system certificates of deposit to the depositor.
(2) If a withdrawal, the depositor to fill out a withdrawal form, and then handed over to the clerk, the clerk to the withdrawal amount entered into the system and requires a password to confirm the identity of depositors, the system calculates interest after checking the password is correct and print list of interest to depositors.
Second, the feasibility study
(1) the technical feasibility of
the prior art, the development of such a system is not difficult, some analysis of existing systems.
. A data flow diagram:
Deposit flowchart b:.
C withdrawals flowchart:
(2) the economic viability of
existing systems required to run expenses include: salaries bank clerk and other staff, system maintenance necessary funds, the bank can meet the above funds, and the system will make the bank learned a lot in the market It benefits, and therefore economic system can exceed its development costs.
(3) the feasibility of operating
the system is simple, easy to use and user acceptance, and the system can quickly feedback on the user's requirements, to make fastest processing information input by the user, to meet customer needs.
In summary, the development of computer systems is feasible savings.
3, for the convenience of passengers, an airline intends to develop a ticket reservation system. The travel agent scheduled to air passenger information (name, sex, place of work, identity card number, travel time, travel destination, etc.) entered into the system, the system for passengers arrange flights, print tickets and billing notice, passengers in the plane took off with the tickets the day before notification and bill payment for the tickets, proofread and correct the system that is printed tickets to passengers. Write the definition of the problem and analyze the feasibility of the system.
First, the problem analysis
(1) goal: to establish within a month of an efficient, error-free airline ticket reservation system
(2) main problems: artificial difficult to manage, cumbersome
(3) to establish a new system
Second, the feasibility study
(1) the economic feasibility of cost-benefit analysis of
a cost estimate: a printer (2000 yuan) + development costs (3500 yuan) = 5500 yuan, may bear.
. b Estimated Benefit: The system has good social benefits and improve the efficiency of airline ticketing, passenger convenience, convenient ticketing and scientific.
(2) technical feasibility
After investigation and analysis, airline ticket reservation system flow chart is as follows:
(3) operational feasibility
comparing two or more seen in FIG, compared with manual systems, the main computer to retain the original workflow can be seen that the computer system is optimized artificial system, nor complicated operation, the staff in a short time after training you can master.
In summary, the development of the airline ticket reservation system is feasible.
5. Beijing university phone numbers are available in the following categories: school phone numbers of four digits, the first digit is not 0; outside phone calls and the city is divided into two types of field telephone, dial the required telephone dial-school 0, then if the city is phone and dial 8 digits (bit 1 is not 0), if the area code field telephone 3 the telephone number dial 8 (1 bit is not 0) is set aside.
The method for defining data tells section 2.5.2, as defined above telephone number.
A: The
phone number = [telephone number campus | outside telephone number]
campus phone number = + 3-digit non-zero number
outside phone number = [number city | Number Field]
city = zero digit number + 8-digit
field number = + 3-digit number zero + 8 digits
nonzero number = [1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9]
the number zero = 0
3 = 3-digit {3} a digital
8-bit digital = 7-digit non-zero number +
7 = 7-digit numbers {7}
numbers = [0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9]
wherein, [] means or telephone from school select a number or a telephone number outside - a; {} represents a repeating digital representation on both sides of lower and upper limits of the number of repetitions; is defined as the mean = mean + ;; and, connecting the two components. .
