C++ Programming Basics
Chapter 1 Lecture
CSIS 10A
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Agenda
Hardware Basics 
The IDE
My First Program
Its all G(r)eek to me
Variables and Declarations
Input and Output
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Anatomy of a Computer
ALU
Control
Input
Mouse
Keyboard
Scanner
Hard Disk
Floppy Disk
Memory
Output
Monitor
Printer
Speakers
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The CPU uses machine language
Assembly instructions to calculate the radius of a
circle:
LOAD
radius
LOAD
pi
MULTIPLY
LOAD
two
MULTIPLY
STORE
circle
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Compilers to the Rescue!
High level languages like C++ allows writing
code that is easier to understand and
universally works on any CPU.
circle=2.0*radius*pi;
The compiler is what translates instructions
from C++ into Machine language.
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Agenda
Hardware Basics
The IDE 
My First Program
Its all G(r)eek to me
Variables and Declarations
Input and Output
6
THE MECHANICS OF WRITING
A PROGRAM
1.
2.
3.
4.
5.
Editing -- Writing a program
Compiling -- Translating from C++ into machine language
Linking -- Combining your program with other libraries
Running – Letting the computer execute a program
Debugging – Running step by step through a program
searching for mistakes
The Integrated Development Environment (IDE) combines 1-5.
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Agenda
Hardware Basics
The IDE
My First Program 
Its all G(r)eek to me
Variables and Declarations
Input and Output
8
Hello World !
Lets start off the traditional way
Program that prints out “Hello World” on
your output console (your screen)
Lets start off on our journey…..
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Steps
1.
2.
3.
4.
5.
6.
Create new source file
Write the code
Create a workspace (only in MSVC++)
Compile
Link
Execute
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Agenda
Hardware Basics
The IDE
My First Program
Its all G(r)eek to me 
Variables and Declarations
Input and Output
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It’s all G(r)eek to me
… actually, its C++
Lets dissect and analyze a simple
program
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20,000 ft. above sea level
#include <iostream>
using namespace std;
int main()
{
// This is my first program
cout << "Hello World" << endl;
system("pause");
return 0;
}
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20,000 leagues under the sea
#include <iostream>
Actually includes some information into
your code
Contains some definitions that are
needed for your code
More of this later on in the course
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22,000 leagues under the sea
using namespace std;
This line refers to a set of standard
object name definitions
For now, this is “boilerplate”—stick it in
cause it makes everything work!!
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… deeper….
int main()
• This is the piece of code (function) that
is operated on first when a program is
executed
• What’s a function ???
• …. all that’s coming soon …
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… even deeper….
//This is my first program
• This is a comment you write to yourself
• Useful when writing large programs
• Starts with a //
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… and deeper…..
Output operator
cout << “Hi”<<endl;
cout is the console monitor (your display)
<< is the output operator. Use to chain
together your output message.
“Hi”is a string literal
endl means end-line (like enter key)
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… getting sleepy?…..
For the Bloodshed environment…Hold
the display open so you can read it
(pressing a key will continue)
system("pause");
Finish up this program, return a 0 to
operating system (everything ended
OK)
return 0;
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… and even deeper ….
{} delineates the code block
Each line ends with a ;
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Other types of cout statement
cout<< “ my age is” <<endl << 39<<endl;
cout<< “ my age is 39”;
cout<< “ what’s your’s”;
Escape with \
Output a “
Output a endl
cout<<“ \” ” <<endl;
cout<<“\n”;
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Tom’s All Purpose Program Shell
#include <iostream>
using namespace std;
int main()
{
// Your code here ...
system("pause");
return 0;
}
Future slides may neglect some of the above components
for clarity
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You Do It
Modify your hello world program to print your
name, address and phone number (COULD BE
FAKE!) on three lines:
Tom Rebold
1600 Pennsylvania Ave
123-456-7890
Experiment with line breaks
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Lets get moving…..
We’ll learn as we proceed
You’ll be saying “Aha!” or “Oho!” when
you hear these terms again
Let’s play around a bit more
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What more ?
Variables and Declarations
Getting User Input
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Variables and Declarations
Variables represent storage locations in
the computer’s memory
variable = expression
Assignment is from right to left
n = 5;
Would give n the value 5
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Using int Variables
int main()
{
int m,n;
m = 44;
cout << “m = “ << m;
n = m + 33;
cout << “ and n = “ << n << endl;
}
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Clearing the haze
int m;
m = 44.0;
m
44
int
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Clearing the haze
int m = 44, n;
n = m + 33;
m
44
int
44 + 33 = 77
n
77
int
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Want more ?
Variables and Declarations
Getting User Input
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User Input with cin
How shall I feed in data ?
Remember cout ?
Meet cin
cin >> m;
Will put the value entered through the
console (keyboard) into m
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User Input with cin
int main()
{
cout << "Enter the value of m:";
cin >> m;
cout << "m = " << m << endl;
}
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User Input with cin
int main()
{
cout << “Enter the value of m:”;
cin >> m;
cout << “m = “ << m << endl;
}
HEY THERE’S
SOMETHING WRONG
HERE !!!
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User Input with cin
int main()
{
int m;
cout << "Enter the value of m:";
cin >> m;
cout << "m = " << m << endl;
}
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Your turn ()
1. from hello.cpp File>SaveAs age.cpp
2. Delete all the cout statements. Add lines to:
a) Declare a variable called age
b) Display a message asking for data
(such as “tell me your age”)
c) read the data into age
d) display the variable age with a descriptive
message. (refer to slide 34)
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That’s a wrap !
What we learned so far:
How to write a basic C++ program
The structure of a program
Displaying to the console (cout)
Variables
Getting user input via the console (cin)
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