The default precision value is 6.

1. Submitted by:- Namita Pandey
2011BTechece020
Shiva Johari

2.  Introduction
 Streams & Stream Classes
 Unformatted Input Output Operations
 Formatted Console Input Output Operation
 Formatting Flags, Bit fields and setf()
 Designing Our Own Manipulators

3.  Managing Console I/O Operations
 INPUT & OUTPUT
 C++ supports a rich set of I/O operations
 C++ uses the concept of stream & stream
classes

4. o A sequence of bytes
o An interface between program and device
INPUT EXTRACTION
STREAM FROM INPUT
INPUT STREAM
DEVICE
PROGRAM
OUTPUT
DEVICE
INSERTION
OUTPUT INTO OUTPUT
STREAM STREAM

5.  C++ contains a hierarchy of classes that are used to define
various streams
ios
INPUT OUTPUT
POINTER
istream streambuf ostream
iostream
Istream_withassign Iostream_withassign Ostream_withassign

6.  Overloaded operators >> and <<
 get() and put() functions
 getline() and write() functions

7. C++ supports a number of features which can
be used for formatting the output. These
features include :-
 ios class functions
 Manipulators
 User-defined Manipulators

8. FUNCTION TASK
 Width()  To specify the required field size for
displaying the output value
 Precision()  To specify the digits to be displayed
after decimal point of a float value
 Fill()  To specify a character that is used to
fill the unused portion of a field
 Setf()  To specify format flags that can
control the form of output display
 Unsetf()  To clear the flags specified

9. MANIPULATORS EQUIVALENT IOS FUNCTION
 setw()  width()
 setprecision()  precision()
 setfill()  fill()
 setiosflags()  setf()
 resetiosflags()  unset()

10. cout.width(5); 5 4 3 1 2
cout<<543<<12<<“n”;
cout.width(5);`
cout<<543;
cout.width(5); 5 4 3 1 2
cout<<12<<“n”;

11. #include<iostream.h> cout.width(8);
cout << cost[i];
int main()
{ int value = items[i] *
int item[4] = cost[i];
{10,8,12,15}; cout.width(15);
int cost[4] =
cout << value <<“n”;
{75,100,60,99};
cout.width(5);
sum =sum + value;
cout << “ITEMS”; }
cout.width(8); cout << “n Grand
cout << “COST”; Total = “;
cout.width(15);
cout << value<<“n”; cout.width(2);
sum =sum + value; cout << sum <<“n”;
int sum = 0;
for(int i=0; i<4;i++) return 0;
{
cout.width(5); }
cout << items[i];

12. ITEMS COST TOTAL VALUE
10 15 150
8 100 800
12 60 720
15 99 1485

13. cout.precision(3); 1.141
cout<<sqrt(2)<<“n”; 3.142
cout<<3.14159<<“n”;
cout<<2.50032<<“n”; 2.5

14. #include<iostream.h>
#include<conio.h>
void main()
{
float pi=22.0/7.0;
int I;
cout<<“Value of pi :n “;
for(i=1;i<=10;i++)
{
cout.width(i+1);
cout.precision(i);
cout<<pi<<“n”;
}
}

15. Value of pi :
3.1
3.14
3.143
3.1429
3.14286
3.142857
3.1428571
3.14285707
3.142857075
3.1428570747

16. cout.fill(‘*’);
cout.width(10);
cout<<5250<<“n”;
* * * * * * 5 2 5 0

17. #include<iostream.h> cout<<“n Paddling Changednn”;
#include<conio.h> cout.fill(‘#’);
void main() cout.width(15);
{ cout<<12.345678<<“n”;
cout.fill(‘<‘);
return 0;
cout.precision(3); }
for(int n=1;n<=6;n++)
{
cout.width(5);
cout<<n;
cout.width(10);
cout<<1.0/float(n)<<“n”;
if(n==3)
cout.fill(‘>’);
}

18. <<<<1<<<<<<<<<1
<<<<2<<<<<<<0.5
<<<<3<<<<<<<0.3
>>>>4>>>>>>0.25
>>>>5>>>>>>>0.2
>>>>6>>>>>0.167
Paddling Changed
#########12.346

19. arg1 - formatting flags defined in the class ios
arg2 - it specifies the group to which the formatting flags belongs

20. FORMAT REQUIRED FLAG (ARG1) BIT-FIELD (ARG2)
Left-justified output ios::left
ios::adjustfield
Right-justified output ios::right
ios::adjustfield
Padding after sign or base ios::internal
ios::adjustfield
Indicator (like +##20)
Scientific Notation ios::scientific
ios::floatfield
Fixed Point notation ios::fixed
ios::floatfield
Decimal Base ios::dec
ios::basefield

21. #include<conio.h>
#include<iostream.h>
main()
{
cout.setf(ios::fixed, ios::floatfield);
float x=1234.67 ;
cout<<x<<endl;
cout.setf(ios::scientific, ios::floatfield);
x=.123467 ;
cout<<x;
getch();
}

22. 1234.668234
1.234672e-01

23. #include<iostream.h>
#include<conio.h>
void main()
{
int num;
cout<<“enter an integer value”;
cin>>num;
cout<<“The hexadecimal, octal and
decimal representation is : ”;
cout.setf(ios::hex, ios::basefield)
cout<<num<<“, “;
cout.setf(ios::oct, ios::basefield)
cout<<num<<“, “;
cout.setf(ios::dec, ios::basefield)
cout<<“ and “<<num<<“ respectively”;
}

24. Enter an integer value : 92
The hexadecimal, octal and decimal
representation of 92 is: 5c, 134 and 92
respectively.

25. ostream & manipulator (ostream & output)
{
……………
…………… (code)
……………
return output;
}

27.  We have taken all the basic ideas about the
concepts from the book “OBJECT ORIENTED
TECHNIQUES” – by E. Balagurusamy
 Images are made in Ms- Paint
 & every thing is accompanied by ideas of our
own

30. The function of istream class is to :
a) inherit the properties of ios
b) Declares input functions such as
get(), getline(), read() etc.
c) Contains overloaded extraction operator >>
d) All of the above

31. The function of streambuf is to :
a) provides an interface to physical devices through buffers
b) Can’t act as a base for filebuf class used for ios files
c) Declares constants and functions that are necessary for
handling formatted i/p and o/p operations
d) None of the above

32. A stream is a sequence of ___________.
a) Bytes
b) Files
c) Manipulators
d) None of the above

33. Which are the member functions of ios class :
a) precision()
b) width()
c) fill()
d) All the above

34. What will be the output of following :
cout.fill(‘*’);
cout.precision(3);
cout.setf(ios::internal, ios::adjustfield);
cout.setf(ios::scientific, ios::floatfield);
cout.width(15);
cout<<-12.34567<<“n”;
-******1.235e+01 (.A B.) -*****1.235e+01
-*****.1235e+02
-*********1.236
(.C D.)

35. a) The __________ operator is overloaded in the istream class
a) Insertion
b) >>
c) <<
d) None of the above

36. Which Class is needed to be virtual in this case :
a.) iostream
b.) ios
c.) istream or ostream
d.) no one is required
ios
INPUT OUTPUT
POINTER
istream streambuf ostream
iostream
Istream_withassign Iostream_withassign Ostream_withassign

37. Q8.
The header file iomanip can be used in place of
iostream ??
Q9.
programmer can’t define a manipulator that could
represent a set of formatted functions ??

38. What is the default precision value ??
a.) 0 b.) 4
c.) 6 d.) 3