1. C++ Programming Basics

2. Overview Basic Program Construction Output using cout Directives
Comments
Integer Variables
Character Variables
Input using cin
Floating Point Types
Type bool
Endl and setw Manipulators
Type Conversion
Arithmatic Operators
Libaray Functions

3. Basic Program Construction
#include <iostream>
int main() {
cout<<” Every age has a language of its own\n ”;
return 0; }
Fucntion Name
Braces and Function Body
Program state ments
White spaces: ignored by compiler such as spaces, carriage returns, linefeeds, tabs

4. Always start with main()
Program entry point
Control always goes to main() before excuting other functions
main() function may also contain calls to other stand alone functions and member functions in various objects

5. Output using Cout<<
Cout is an object predefined in C++ corresposnds to the standard output stream
Standard output stream flows to the screen display
Cout<<”Every age has a language of its own \n”;
<< Operator is called insertion or put to operator
String Constant is array of characters and retains its value throughout the program existance

6. Directives Preprocessor Directives It is instruction to the compiler
A part of compiler called preprocessor deals with directives before it begin real compilation process.
E.g. #include <iostream.h>
#include tells compiler to insert another file into source file
Same as pasting a block of text into a document with your word processor

7. Directives Using Directive C++ program is divided into namespaces
A namespace is part of the program in which certain names are recognized; outside namespace they are unknown
E.g. Using namespace std;
All program statements within std namespace
Used when working in multifiles environment
If not using directive then we need to add
Std::cout<<”Hello World”;

8. Comments Helps in understanding code: Optional Syntax
// single line comment
/*this is multiline comment*/
Can be inserted anywhere in program

9. Variables Variable has symbolic name and can have varity of values
Variables are located in particular location in computer memory
Declaration introduce variable’s name and specify its type such as int
Int a;
Long num;
Definition introduce intialization of variable
Int a = 10;
Identifer vs keyword
Assignment statements
var1 = 20;
var2 = var1 + 10;

10. Integer Variables
Integer variables represent integer numbers like 1,30,000 and - 26
The amount of memory occupied by integers is system dependent
32 bit system such as windows allows int to occupy 4 bytes
Ranges occupied by various types are listed in header file LIMITS

11. Character Variables
Type char stores integer having range from -128 to 127
Occupy only 1 byte of memory
Commonly use to store ASCII characters such as ‘a’, ‘B’, ‘$’, ‘3’ etc
Character Constants vs String Constant
Character constant is translated into equivalent in ASCII code e.g. Constant ‘a’ will be translated into 97
Escape Squences
\ causes an escape from normal way character are interpreted
\ t, \ n, \ \

12. Input with cin>>
Keyword cin in an object defined in C++ to correspond to standard input stream.
>> is the extraction or get from operator
#include<iostream>
Using namespace std;
Int main() {
int ftemp;
cout <<”Enter temperature in fahrenheit: ”;
cin>>ftemp;
int ctemp = (ftemp – 32) * 5/9;
cout<<”Equivalent in Celsius is: ”;<<ctemp<<‘\n’;
return 0; }

13. Floating Point Types
Floating point variables represent numbers with decimal place e.g , and -10.2
Float
Stores number in range 3.4 x to 3.4 x 10 38
Seven digits precision
Double
8 bytes of storage and handles number in range from 1.7 x to 1.7 x
15 digits precision

14. Constants Const Qualifier
const float PI = F; // type const float
Value of variable will not change throughout the program
#define Directive
Can also be specified using #define directive
#define PI
PI will be replaced by its value throughout the program

15. Variable Type Summary Name Description Size* Range* char
Character or small integer.
1byte
signed: -128 to 127 unsigned: 0 to 255
short int (short)
Short Integer.
2bytes
signed: to unsigned: 0 to 65535
int
Integer.
4bytes
signed: to unsigned: 0 to
long int (long)
Long integer.
bool
Boolean value. It can take one of two values: true or false.
true or false
float
Floating point number.
+/- 3.4e +/- 38 (~7 digits)
double
Double precision floating point number.
8bytes
+/- 1.7e +/- 308 (~15 digits)
long double
Long double precision floating point number.
wchar_t
Wide character.
2 or 4 bytes
1 wide character

16. Setw and endl Manipulator
Manipulators are used with insertion operator (<<) to modify or manipulate the way data is displayed
Endl manipulator for new line
setw() manipulator causes the number(string) that follows it in the stream to be printed within a field n characters wide
n is argument to setw(n)
Right justified
IOMANIP header file used for these manipulators

17. Type Conversion Automatic Conversion Casts ?
When two operands of different data types are encountered in the same expression ,the lower type variable is converted to the type of higher type variable.
Casts ?

18. Arithmetic Operators + addition - subtraction * multiplication /
division %
Modulo/Remainder

19. Arithmetic Assignment Operator
Combines an arithmetic operator and an assignment operator and eliminate repeated operand
total = total + items can be writen as total+=items
Increment Operator
Add 1 to the value of an existing variable
E.g. count = count +1 // adds 1 to count
Count +=1; // adds 1 to count
++count; // adds 1 to count

20. Cont’d Increment operator can be used in two ways Prefix Postfix
Operator preceeds the variable
TotalWeight = avgWeight * ++count;
Postfix
Operator follows variable
totalWeight = avgWeight * count++;
Decrement Operator (--)
Same as increment but subtracts 1 from its operand
Can be used in both prefix and post fix forms

21. Library Functions
Many activities in C++ are carried out by library functions
Performs file access, mathematical computation and data conversions
E.g. Sqrt(number) is libaray function in cmath header file
Header File
File that contain declaration of any library functions used
E.g. #include <cmath> header file of SQRT() function

22. Library files vs Header files
Library files contain actual machine-executable code for functions
Have .lib file extension
Sqrt() function is part of library files
Automatically extracted from by the linker
Header files contain information for particular group of functions
Two Ways to use #include
#include ”myheader.h” // search in current directory
#include<cmath>
Search for particular header file in INCLUDE directory