The Software Construction Process

1
The Software Construction Process
2
Computer System Components
Internet
Primary Storage (RAM)
Network Interface Devices (Modem, Network Card)
01001101 10110101 11011001 10110100 00101011 01011
001 10101010 01011011 10100110 01001011
Output Devices (Monitor, Printer)
Input Devices (Mouse, Keyboard)
Communications Bus
Secondary Storage (Hard Drive, CD-ROM Drive)
Central Processing Unit (Microprocessor)
3
A Software Requirement
Develop a program that finds and prints all
numbers between 1 and 10,000 that are divisible
by both 7 and 3. For each number found, display
the number and the product of the two quotients.
4
The Requirement and the Design
S
Set number to 1
Develop a program that finds and prints all
numbers between 1 and 10,000 that are divisible
by both 7 and 3. For each number found, display
the number and the product of the two quotients.
No
Number less than or equal to 10,000
Yes
No
Number divisible by 7
Yes
No
Number divisible by 3
Yes
Print number information
Increment number by 1
F
5
Boards, Tubes, and Patch Cables
Application Program
01001101 10110101 11011001 10110100 00101011 01011
001 10101010 01011011 10100110 01001011
6
Setting Switches
Application Program
01001101 10110101 11011001 10110100 00101011 01011
001 10101010 01011011 10100110 01001011
7
I/O Devices and Operating System
01010101 10101010 10101110 01001011
Operating System
01001101 10110101 11011001 10110100 00101011 01011
001 10101010 01011011 10100110 01001011
Application Program
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Assembly Language, Monitor, and Keyboard
01010101 10101010 10101110 01001011
Operating System
10111010 10101010 01011011
Assembler
01001101 10110101 11011001 10110100 00101011 01011
001
LOOP LOAD A, R1 LOAD 7, R2 TEST R1, R2 BRZ
LOOP
Application Program
9
Compiler (Syntax and Semantics)
01010101 10101010 10101010
Operating System
10111010 10101110 01001011
include ltstdio.hgt int main (void) int
anAnswer float aValue anAnswer aValue /
3 printf(d\n,anAnswer) return 0
Assembler
10101011 00101010 01101011
Compiler
11011001 10110100 00101011 01011001
Application Program
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Algorithm in C Source Code
aNumber LOWNUMBERwhile (aNumber lt
HIGHNUMBER) firstQuotient aNumber /
FIRSTDIVISOR if ( (aNumber FIRSTDIVISOR)
0 ) secondQuotient aNumber /
SECONDDIVISOR if ( (aNumber
SECONDDIVISOR) 0)
theProduct firstQuotient secondQuotient
printf("d 7.2f 7.2f 8.2f\n",aNumber,
firstQuotient, secondQuotient,
theProduct) // End if // End
if aNumber // Increment aNumber by one
Note This is only a portion of the complete C
program
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From Requirements to Running Program
Software Requirements
Design Fundamentals
Design Method
Software Design
Coding Standards
Text Editor
program.c (Source Code)
C Header Files
Compiler (and Preprocessor)
program.o (Object Code)
Function Libraries
Linker
program.exe (Executable Code)
Input/Output Facilities
Operating System
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Software Construction Process
Requirements
1
COMPILE
DESIGN
2
3
4
8
EDIT and SAVE
A
LINK
BASELINE
E
B
D
C
5
7
RUN
TEST and SQA
6
Note See next slide for meanings of A - E
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Categories of Errors

• A Compiler errors doesnt follow preprocessor
  or C syntax
• B Linker errors functions declared but not
  defined no main function function library not
  found
• C Run-time errors segmentation fault
  out-of-range errors wrong data types
• D Logic errors wrong use of control
  statements errors in function arguments
  algorithm coded incorrectly
• E Design errors doesnt follow design or
  satisfy requirements design has flaws

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