1. The Software Construction Process

2. Computer System Components
Internet
Primary Storage
(RAM)
Network Interface Devices
(Modem, Network Card)
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
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

6. Setting Switches Application Program 01001101 10110101 11011001

7. I/O Devices and Operating System
Operating
System
Application
Program

8. Assembly Language, Monitor, and Keyboard
Operating
System
Assembler
LOOP: LOAD A, R1
LOAD 7, R2
TEST R1, R2
BRZ LOOP
Application
Program

9. Compiler (Syntax and Semantics)
Operating
System
#include <stdio.h>
int main (void) {
int anAnswer;
float aValue;
anAnswer = aValue / 3;
printf(“%d\n”,anAnswer);
return 0; }
Assembler
Compiler
Application
Program

10. Algorithm in C Source Code
aNumber = LOWNUMBER; while (aNumber <= 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

11. From Requirements to Running Program
Design Fundamentals
Software Requirements
Design Method
Coding Standards
Software Design
Text Editor
C Header Files
program.c (Source Code)
Compiler (and
Preprocessor)
Function Libraries
program.o (Object Code)
Linker
Input/Output Facilities
program.exe (Executable Code)
Operating System

12. Software Construction Process
Requirements 1
DESIGN
COMPILE 2 3 8
EDIT and
SAVE 4 A
BASELINE
LINK E B D C 7 5
TEST and
SQA
RUN 6
Note: See next slide for meanings of A - E

13. Categories of Errors
A: Compiler errors – doesn’t 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 – doesn’t follow design or satisfy requirements; design has flaws 