1. COSC 120 Computer Programming
Instructor: Dr. Enyue (Annie) Lu
Office hours: click here
Office room: HS114
Course information:
Website:
Course schedule: Dates and topics are subject to change as required by class progress

2. Course overview Optional topics Introduction to class Pointers
Introduction to Programming
Introduction to C++
Data types
Control structures
Functions
Scope, overloading functions, files
Arrays
Searching & Sorting Arrays
Characters, Strings, and the string Class
Structured Data
Introduction to class
Pointers
Operator overloading
Optional topics

3. Chapter 1 Introduction to Computers and Programming

4. Contents Why Program? Computer Systems: Hardware and Software
Programs and Programming Languages
What Is a Program Made of?
Input, Processing, and Output
The Programming Process
Procedural and Object-Oriented Programming

5. Why Program:
Program: a set of instructions to a computer to perform a task
Computer can do many different jobs because of its programmability.
Programmer->software->computer

6. Elements of a Computer System
Hardware
CPU (central processing unit): CU, ALU
Fetch/decode/execute
Main Memory: RAM
Byte, bits
Memory address
volatile
Secondary storage
Programs are stored in secondary memory and loaded into main memory
Hard disks, floppy disks, Zip disks and CD
Input/Output devices
Software

7. Software – Programs That Run on a Computer
Categories of software:
Operating system:
programs that manage the computer hardware and the programs that run on them. Ex: Windows, UNIX, Linux
- Single tasking, multitasking
- Single user, multiuser
Application software:
programs that provide services to the user. Ex: word processing, games, programs to solve specific problems
All computer systems consist of similar hardware devices and software components:

8. Programs and Programming Languages
Program: a set of instructions to a computer to perform a task
Programming Language: a language used to write programs

9. Programs and Programming Languages
Types of languages:
Low-level (machine): used for communication with computer hardware directly. Often written in binary machine code (0’s/1’s) directly.
High-level: closer to human language
A compiler or interpreter are programs that make the translations from high-level to low-level languages.

10. Table 1-1

11. From a High-level Program to an Executable File
connect hardware-specific code (library routines) to machine instructions, producing an executable file
convert source file directives to source code program statements
Object Code
Source Code
Linker
Preprocessor
convert source program statements into machine language instructions
a) Code the program with a text editor or using an IDE. (IDE(p11): integrated development environments (eg: Microsoft Visual C IDE)
b) Run preprocessor to convert source file directives to source code program statements.
c) Run compiler to convert source program statements into machine language instructions.
d) Run linker to connect hardware-specific code to machine instructions, producing an executable file.
Steps b–d are often performed by a single command or button click.
Errors detected at any step will prevent execution of following steps.
Modified
Source Code
Executable Code
Compiler

12. What Is a Program Made Of?
Common elements in programming languages:
Key Words
Programmer-Defined Symbols
Operators
Punctuation
Syntax

13. Language Elements, Table 1-2
AKA: also known as

14. Example Program #include <iostream> #include <string>
using namespace std;
int main() {
string name;
cout << "What is your name? ";
cin >> name;
cout << "Hello there, " << name;
return 0; }
(#: pound sign)
Key words: using, namespace, int, main
Programmer-Defined Symbols: ( Identifiers ):name, hours, rate, calcPay()

15. Program 1-1 // This program calculates gross pay.
#include <iostream>
using namespace std;
int main() {
float hours, rate, pay;
cout << “How many hours did you work? ”;
cin >> hours;
cout << “How much do you get paid per hour? ”;
cin >> rate;
pay = hours * rate;
cout << “You have earned $” << pay << endl;
return 0; }

16. Key Words Also known as reserved words Have a special meaning in C++
Can not be used for another purpose
Examples in program:
using, namespace, int, main

17. Programmer-Defined Symbols ( Identifiers )
Names made up by the programmer
Not part of the C++ language
Used to represent various things:
variables (memory locations), functions, etc.
Example in program:
name, hours, rate, calcPay()

18. Operators Used to perform operations on data Many types of operators:
Arithmetic: +, -, *, /
Assignment: =
Examples in program:
<< stream insertion operator
>> stream extraction operator

19. Punctuation
Characters that mark the end of a statement, or that separate items in a list
Examples in program:
; (),}
Semi-colon
Parentheses
Braces

20. Syntax
The rules of grammar that must be followed when writing a program
Controls the use of:
key words
operators
programmer-defined symbols
punctuation
Class 1

21. Lines and Statements cout << "How many hours did you work? ";
There are 2 statements above.
The first statement uses one line
the second statement spans two lines
the semicolon ( ; ) is the statement terminator
The contents of a program are thought of in term of lines and statements

22. Variable Definitions float hours, rate, pay; Two types of information:
numbers and characters
Numbers may be integers or floating-point
The statement below creates three variables in memory named hours, rate, and pay that each can store a floating-point number
float hours, rate, pay;

23. Input, Processing, and Output
Three steps many programs perform:
Gather input data:
from keyboard
from files on disk drives
Process the input data
Generate output:
send it to the screen
write it to a file

24. Input, Processing, and Output
cout << "Enter your hours and rate " << "separated by a space: ";
Input:
cin >> hours; cin >> rate;
Processing:
pay = hours * rate;
cout << “You have earned $” << pay;

25. Program Output How many hours did you work? 10
How much do you get paid per hour? 15
You have earned $150

26. The Programming Process
The programming process consists of several steps, which include:
Design
Code
Test
Debug
Document

27. The Programming Process
Clearly define what the program is to do. Purpose, Inputs /Outputs, Process
Visualize the program running on the computer
Design using a Hierarchy chart, flowchart or pseudocode.
Desk check for logical errors.
Enter/Edit the code and compile it.
Correct any errors found during compilation.
Compile-time error (syntax/grammatical error)
Repeat steps 5 and 6 as many times as necessary
Run the program with test data for input
Correct any errors found while running the program
Run-time errors
Repeat steps 5 through 8 as many times as necessary.
Validate the results of the program.
Use the Example in page 18

28. Procedural and Object-Oriented Programming
Procedural programming: focus is on the process. Procedures/functions are written to process data.
Object-Oriented programming: focus is on objects, which contain data and the means to manipulate the data. Messages are sent to objects to perform operations.

29. Class Review Program Why computer can do lots of job
A set of instructions to a computer to perform a task
Why computer can do lots of job
Programmability
Elements of computer system
Hardware (CPU, main memory, second storage, I/O), software
Software categories
OS, application software
Programming languages
Low-level, high-level
Transfer a high-level program to an executable file
Preprocess, compile, link
Common elements in programming languages
Keyword, programmer-defined symbols, operators, punctuation, syntax
Which 3 steps most programs perform
Gather input data, process data, generate output