3. Ios:
It contains basic facilities that are used by all other
input and output classes.
Istream:
It inherites the properties of ios and it declares input
functions such as get(),getline() and read().
Ostream:
It inherites the properties of ios and it declares
output functions such as put() and write().
Iostream:
It inherites the properties of ios stream and ostream.
Streambuf:
It provides an interface to physical devices through
buffers.
4. The features that supports to format the console
I/O operations are:
ā¦ Ios class functions and flags
ā¦ Manipulators
ā¦ User-defined output functions
IOS CLASS FUNCTIONS AND FLAGS:
It consists of large number of member functions
that is used to format the output in number of ways.
5. ļ½ MANIPULATORS:
These are the special functions that are
included in the I/O statements to format the
parameters of a stream.
ļ½ DEFINING FIELD WIDTH:
ā¦ It is used to define the width of the field.
ā¦ Can be defined using width();
ļSETTING PRECISION:
It is used to specify the to be displayed after the
decimal point.
ļ¶FILLING AND PADDING:
ļ§ It is used to print the values using the larger field
widths.
ļ§ It can be declared by,
cout.fill();
6. #include <iostream>
using namespace std;
int main()
{
int item[4] ={ 10,8,12,15};
int cost[4]={75,100,60,99};
cout.width(5);
cout<<āItemsā;
cout.width(8);
cout<<āCostā;
10. It is used for defining the input and output in
various forms.
Overloaded Operators >> and <<:
ā¢ It is used to give the I/O
ā¢ The >> is overloaded in istream class
ā¢ The << is overloaded in ostream class
Ex:
cin>>item1>>item2;
11. put() and get() Functions:
ā¦ It is used for the input and output .
ā¦ Put(c) is used to give the input
ā¦ Get(c) is used to get the output
EXAMPLE:
#include <iostream>
using namespace std;
int main()
{
int count=0;
char c;
cout<<āINPUT TEXT nā;
cin.get( c );
while ( c 1=ānā )
12. while ( c 1=ānā )
{
cout.put( c);
count++;
cin.get( c );
}
cout<< ān Number of characters =ā <<count <<ānā;
return 0;
}
OUTPUT:
Object oriented programming
Number of characters=27
13. Getline() and write() Functions:
ā¢ The getline() function reads a whole line of the
text and ends with a newline character.
ā¢ This function can be invoked by,
cin.getline (line,size);
ā¢ The writeline() function reads a whole line of the
text and displays an entire line.
ā¢ This function can be invoked by,
cout.write (line,size);
14. EXAMPLE:
#include <iostream>
using namespace std;
int main()
{
int size=20;
char city[20];
cout<<āenter city name:n ā;
cin>>city;
cout<<ācity name:ā<<city<<ānnā;
cout<<āenter city name again: nā;
cin.getline(city,size);
16. OUTPUT:
first run
Enter city name:
Delhi
Enter city name again:
City name now:
Enter another city name:
Chennai
New city name:
Chennai
17. ļ½ The header file iomanip provides a set of functions
called manipulators which can be used to manipulate
the output formats.
ļ½ They provide the same features as that of the ios
member function and flag.
ļ½ Two or more manipulators can be,
Cout<<manip1<<manip1<<manip<<item;
Cout<<manip1<<item1<<manip2<<item2;
20. ļ½ The large amount of Data can be handled using some
devices such as floppy disk or hard disk to store those
datas.
ļ½ These datas are stored in these devices called FILES.
ļ½ The Programs can be designed to perform the read and
write operations on those files.
ļ½ Kinds of Data Communication:
ā¦ Data Transfer between the console unit and the
program.
ā¦ Data Transfer between the program and a Diskfile.
21.
22. FILEBUF:
It is used to set the file buffers to read and write.
FSTREAMBASE:
It provides operations common to the file streams.
IFSTREAM:
It provides input operations.
OFSTREAM:
It provides output operations.
FSTREAM:
It provides support for both input and output
operations.
23. ļ½ The I/O system contains a set of classes that define
the file handling methods.
ļ½ These includes ifstream, ofstream and fstream.
ļ½ These classes are derived from fstreambase and from
the corresponding iostream class.
ļ½ These classes are designed to manage the Disk files,
which are declared in fstream and we should include
any program in these files.
24. ļ A file stream can be declared using the classes
ifstream, ofstream and fstream that are contained in
the Header file fstream.
ļ A file can be Opened into two ways:
ļUsing the Constructor function of the class
ļUsing the Member function open() of the class
OPENING FILES USING Open():
ļ The function open() can be used to open multiple
files that use the same stream object.
file-stream-class stream-object;
stream-object.open (āfile nameā);
27. This condition is necessary for preventing data
from the file. This condition is
MORE ABOUT OPEN( ): FILE MODES
ā¢ The ifstream and ofstream is used to create
the new files.
ā¢ The function open( ) is used to open a new
stream.
object. open(āfile nameā,mode);
28. Each file has two associated pointers known
as File pointers.
DEFAULT ACTIONS:
When we open a file in read-only-mode
,these input pointer is automatically set at the
beginning.
FUNCTIONS FOR MANIPULATION OF FILE POINTERS:
ļ§ seekg()-Moves a pointer to specified location
ļ§ seekp()-Moves put pointer to a specified location
ļ§ tellg()-Gives the current position of the get pointer
ļ§ tellp()-Gives the current position of the put pointer
29. It supports a number of member function for
performing the input/output operations on files.
Put() and get() Functions:
ā¦ It is used to handle single character at a time.
ā¦ The function put() writes a single character to the
associated stream.
ā¦ The function get() reads a single character to the
associated stream.
Write() and read() Functions:
It is used to read and write the blocks in the binary
data.
30. ļ½ It is used to maintain the routine task in the data file.
ļ½ The updation can be done in:
ā¦ Displaying the contents of a file
ā¦ Modifying an existing item
ā¦ Adding a new file
ā¦ Deleting an existing file
31. ļ½ The reading and writing files may not be true
always.
ā¦ A file which we are attempting to open for reading
does not exist.
ā¦ The file name used for a new file may already exist.
ā¦ We may use an invalid file name.
ā¦ There may not be any space in the disk for storing
more data.
ā¦ We may attempt to perform an operation when the
file is not opened for that purpose.
32. ļ½ This feature facilities the supply of arguments to the
main() function.
ļ½ These arguments are supplied at the time of invoking
the program.
ā¦ C> exam data results
ā¦ Exam is the name of the file containing the program
to be executed ,data and results are the filenames
passed to the program as command-line arguments.