Basic_elements

1. Basic Elements of C++
09/04/131 VIT - SCSE
By
G.SasiKumar., M.E., (Ph.D).,
Assistant Professor
School of Computing Science and Engineering
VIT University

2. Characters are used to form the words, numbers and
expressions.
 alphabets from A.....Z, a....z
all decimal digits from 0....9
characters , . ; : ?
‘ “ ! | / ~ _ $ % # & ^
* - + < > ( ) [ ] { } Spaces
blank
New Line endl
09/04/132 VIT - SCSE
Character Set

3. Keywords and Identifiers
All keywords must be written in lowercase.
auto double int struct break
else long switch case enum register
Typedef char extern return union
const float short unsigned continue
for signed void default goto
sizeof volatile do if static while
Identifiers refer to the names of variables, functions and arrays.
These are user -defined names and consist of a sequence of letters
and digits.
09/04/133 VIT - SCSE

4. Data Types
09/04/134 VIT - SCSE
C++ Data Types
User Defined type
Structure
Union
Class
Enumeration
Built-in type Derived type
Array
Function
Pointer
Integral Floating
Character
Void
byte short int long
float double

5. Constants
Constants in C++ refer to fixed values that do not change
during the execution of a program.
C++ supports several types of constants as shown below: -
1. Numeric Constants
Integer Constants
Floating point (real) Constants
2. Character Constants
Single Character Constants
String Constants
09/04/135 VIT - SCSE

6. Integer Constants
Decimal integers consist of a set of digits from 0
through 9. The decimal integers can be positive or
negative.(base 10)
Octal integers consist of any combination of digits
from 0 through 7, with a leading zero.(base 8)
Hexadecimal integers consist of a sequence of digits 0
through 9 and alphabets from A (a) through F (f). The
letters 'A' (a) through 'F ' (f) represent the integers 10
through 15.(16)
09/04/136 VIT - SCSE

7. Floating-Point Constants
Floating-point constants are represented by numbers
containing fractional parts like in 549.4545.
Floating-point constants are also sometimes called as real
number constants.
09/04/137 VIT - SCSE

8. Single Character Constants
A character constant is a single character enclosed within a pair of single
quotes.
Example:
'A'
'3'
'?'
';'
' '
Constant ASCII value
'a' 97
'A' 65
'&' 38
';' 59
09/04/138 VIT - SCSE

9. String Constants
 A string constant is a sequence of characters enclosed
within a pair of double quotes.
The string constant may also include special characters,
numbers and blank spaces.
Example:
" Hello!"
" I'm going for shopping today. Will you come?"
" 549, The Mall, Shimla."
09/04/139 VIT - SCSE

10. Escape Sequences
Character Escape sequence
bell a
backspace b
horizontal tab t
vertical tab v
newline n
carriage return r
quotation mark "
apostrophe '
backslash
null 0
09/04/1310 VIT - SCSE

11. Variables
A variable is an identifier that is used to represent a single data
item
Declaration
Definition
09/04/1311 VIT - SCSE

12. Operators
An operator is a symbol that tells the compiler to perform
specific mathematical or logical manipulations.
Arithmetic Operators
o Increment and Decrement Operators
Relational and Logical Operators
Assignment Operators
Ternary(Conditional) Operator
Sizeof Operator
Comma Operator
& Operator
 -> Operators(a->b -Member b of object pointed to by a )
09/04/1312 VIT - SCSE

13. Control Statements
Conditional Statements
If statement
If-else statement
Switch-case statement
Loop Statements
For loop
While loop
Do-while loop
Breaking control statements
Break
Continue
goto
09/04/1313 VIT - SCSE

14. Switch statement
switch(expression)
{ case constant_1:
statement;
break;
case constant_2:
statement;
break;
-----------------
case constant_n:
statement,
break;
default:
statement;
break;
}
09/04/1314 VIT - SCSE

15. //A program to display the name of the day in a week, depending upon the
number entered through the keyboard using the switch-case statement.
09/04/1315 VIT - SCSE
#include<iostream.h>
void main()
{
int day;
cout<<”Enter a number between 1 to
7”<<endl;
cin>>day;
switch(day)
{
case 1:
cout<<”Monday”<<endl;
break;
case 2:
cout<<”Tuesday”<<endl;
break;
case 3:
cout<<”Wednesday”<<endl;
break;
case 4:
cout<<”Thursday”<<endl;
break;
case 5:
cout<<”Friday”<<endl;
break;
case 6:
cout<<”Saturday”<<endl;
break;
case 7:
cout<<”Sunday”<<endl;
break;
}
}

16. For statement
//A program to find the sum and average of given numbers.
09/04/1316 VIT - SCSE
#include<iostream.h>
void main()
{
int n;
cout<<”How many
numbers?”<<endl;
cin>>n;
float sum=0;
float a=0;
float a;
for(int i=0; i<=n-1;i++)
{
cout<<”Enter a
number”<<endl;
cin>>a;
sum=sum+a;
}
float av;
av=sum/n;
cout<<”sum=”<<sum<<endl;
cout<<”Average=”<<av<<endl;
}

17. Nested For Statement
A program to display a name 15 times using the nested for loops.
#include<iostream.h>
void main()
{
cout<<”Nested for loop”;
for(int i=0; i<=2; i++)
{
cout<<i;
for(int j=0;j<=2;j++)
{
cout<<j;
for(int k=0;k<=2;k++)
{
cout<<k;
}}}}
09/04/1317 VIT - SCSE

18. While statement
{
sum+=digit;
digit++;
}
cout<<“1+2+3+.....
+100=“<<sum<<endl;
}
09/04/1318 VIT - SCSE
//program to find the sum
of the first 100 natural
numbers
#include<iostream.h>
void main()
{
int sum,digit;
sum=0;
digit=1;
while(digit<=100)

19. Do while loop
do
{
sum=sum+digit;
digit=digit+2;
}
while(digit<=max);
cout<<“2+4+...=“<<max<<“su
m=“;
}
09/04/1319 VIT - SCSE
//program to find the sum of
the even numbers using do-
while loop.
#include<iostream.h>
void main()
{
int max,sum,digit;
digit=2;
cout<<“enter a number“;
cin>>max;
sum=0;

20. Break statement
if(a<=0)
{
cout<<”Zero or negative
value found”;
break;
}
i++;
}
}
09/04/1320 VIT - SCSE
#include<iostream.h>
void main()
{
int a,i;
i=0;
while(i<=10)
{
cout<<”Enter a
number”<<endl;
cin>>a;

21. Continue statement
if(a<=0)
{
cout<<”Zero or negative
value found”;
continue;
}
i++;
}
}
09/04/1321 VIT - SCSE
#include<iostream.h>
void main()
{
int a,i;
i=0;
while(i<=10)
{
cout<<”Enter a
number”<<endl;
cin>>a;

22. Goto statement
output1:
cout<<”largest value=”<<a<<endl;
goto stop;
output2:
cout<<”largest value=”<<b<<endl;
stop:
getch();
}
09/04/1322 VIT - SCSE
#include<iostream.h>
#include<conio.h>
void main()
{
int a,b;
cout<<”Enter two
numbers;
cin>>a>>b;
if(a>b)
goto output1;
else
goto output2;
goto label;