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C++ programming language part- 69 File Pointers

November 06, 2017 bappi ashraf

File Pointers

The C++ input and output system manages two integer values associated with a file. One is the get pointer, which specifies where in the file the next input or read operation will occur. the other is the put pointer, which specifies where in the file the next output or write operation will occur. The seekg() and tellg() functions allow you to set and examine the get pointer, and seekp() and tellp() function perform these same actions on the put pointer.

The tellg() and tellp() can be used to find out the current position of the file pointer in the file. The seekg() member function takes two arguments. Suppose: Fil.seekg(10, ios::beg) means , "position the get pointer 10 bytes from the biginning of the file". The first argument is an integer specify the number also called offset . There are three referance points defined on the ios class.

@ ios::beg - the beginning of the file

@ ios::cur - the current position of the file pointer

@ ios::end - the end of the file

consider the following program, which finds out the member of records in the a file.

Program 47_6

class bill

{

public:

int bill_no;

float bill_amt;

};

void main()

{

bill obj;

fstream bfil("bilfile.txt",ios::in); // ask your faculty about fstream and o/ifstream

bfil.seekg(0,ios::end);

int end;

end=bfil.tellg();

cout<<"The size of the file is "<

cout<<"Size of one record is "<

int No_rce=end/sizeof(bill);

cout<<"There are "<

}

part: 01 Programming Language

part: 02 Compiler

part: 03 Programming Logic

part: 04 Data Type

part: 05 Programming in C++

part: 06 Data Type

part: 07 Get Input from keyboard

part: 08 Operators

part: 09 Arithmetic AssignmentOperators

part: 10 Identifies of Characters

part: 11 do.. while loop

part: 12 unary operators( Incrementand decrement)

part: 13 Decrement

part: 14 for loop

part: 16 Conditional/ternary Operator

part: 17 Break

part: 18 The continue statementforces the next iteration of the loop to take place.

part: 19 Arrays

part: 20 Array Address

part: 21 Arrays and Pointer

part: 22 Two dimensional array

part: 23 Function

part: 24 Function Argument

part: 25 Calling Function

part: 26 Return Values

part: 27 Over Loading Function

part: 29 More about function andothers

part: 30 Passing arrays to function

part: 31 Dynamic memory allocation

part: 32 Library function

part: 33 User define mathematicalfunction (square)

part: 34 I/O Function

part: 35 Boolean Functions

part: 36 Look here's two differentuser define Boolean Functions

part: 37 Function Scope

part: 38 String

part: 39 String I/O

part: 40 Some dafault member function

part: 41 Standard String-Handlingfunction

part: 42 String Array

part: 43 User defined data type

part: 45 Data Storage Type

part: 46 Sratic storage type

part: 47 Extern storage type

part: 48 Classes and Objects

part: 49 Scope Resolution Operator

part: 50 Constructor

part: 51 Destructor

part: 52 Inheritance

part: 53 Overriding Base ClassMembers

part: 54 Scope Resolution with OverriddenMembers

part: 55 Base Class Initialization

part: 56 Multiple Inheritance

part: 57 Protected base ClassInheritance

part- 58 Ambiguity of MultipleClasses

part- 59 Virtual Base Class

part- 60 More about Constructor andDestructor

part- 61 Virtual Function andpolymorphism

part- 62 Virtual function withdynamic polymorphism

part- 63 Streams

part- 64 File Input and Output withabstract data types

part- 65 Writing and Readingcharacter using binary functions

part- 66 The get() function

part- 67 String Input

part- 68 Integer Input and Output

part- 69 File Pointers

part- 70 More abuot Integer Input and Output

part- 71 Exercise:

part- 72 Operator overloading

part- 73 Look here is a program witha class and overload the ==,>,< and += operators

part- 74 Linked List

part- 75 Representing a Node

part- 76 Inserting and Traversing a Node

part- 77 Deleting a Node

part- 78 More about Linked List

part- 79 Programming Logic andTechnique

part- 81 Programming Logic and Technique:

part- 82 Programming Logic andTechnique:

part- 83 Programming Logic andTechnique:

part- 84 Programming Logic andTechnique:

part- 85 Programming Logic and Technique:

Part- 86 assign the content of twostring