C++ Tutorial Index

C++ Tutorial C++ History C++ Installation C++ First Program C++ cin and cout C++ Data type C++ Variable C++ operator C++ Keywords

C++ Control Statements

C++ If C++ Nested if C++ If-else C++ If-else-if C++ Switch C++ Break C++ Continue C++ Goto C++ For loop C++ While loop C++ Do while loop

C++ Functions

C++ Call by Value C++ Call by Reference C++ Recursion Function C++ Inline function C++ Friend function

C++ Arrays

Single dimension array Two dimension array

C++ Strings

C++ Strings

C++ Inheritance

C++ Inheritance Single level Inheritance Multilevel Inheritance Multiple Inheritance Hierarchical Inheritance Hybrid Inheritance

C++ Polymorphism

C++ Polymorphism C++ Overloading C++ Overriding C++ Virtual Function

C++ Pointers

C++ Pointers C++ this pointer

C++ Exception Handling

C++ Exception Handling

C++ Constructors

C++ Constructors Default Constructor Parameterize Constructor Copy constructor Constructor Overloading Destructor

C++ File Handling

C++ File Handling C++ Writing to file C++ Reading file C++ Close file

Miscellaneous

C Vs C++ C++ Comments C++ Data Abstraction C++ Identifier C++ Memory Management C++ Storage Classes C++ Void Pointer C++ Array To Function C++ Expressions C++ Features C++ Interfaces C++ Encapsulation std::min in C++ External merge sort in C++ Remove duplicates from sorted array in C++ Precision of floating point numbers Using these functions floor(), ceil(), trunc(), round() and setprecision() in C++ C++ References C++ Friend Functions C++ Mutable keyword Unary Operators in C++ Initialize Array of objects with parameterized constructors in C++ Differences between #define & const in C/C++ C++ Program to Implement Shell Sort C++ Program to Implement Merge Sort Storage Classes in C Vector resize() in C++ Passing by Reference Vs. Passing by the pointer in C++ Free vs delete() in C++ goto statement in C and C++ C++ program to read string using cin.getline() C++ String Concatenation Heap Sort in C++ Swap numbers in C++ Input Iterators in C++ Fibonacci Series in C++ C ++ Program: Alphabet Triangle and Number Triangle C++ Program: Matrix Multiplication C++ Program to Print Fibonacci Triangle Stack in C++ Maps in C++ Queue in C++ C++ Bitset C++ Algorithms Priority Queue in C++ C++ Multimap C++ Deque Function Pointer in C++ Sizeof() Operators in C++ C++ array of Pointers free() Vs delete in C Timsort Implementation Using C++ CPP Templates C++ Aggregation C++ Enumeration C++ Math Functions C++ Object Class C++ Queue Initialize Vector in C++ Vector in C++ C++ STL Components Function overloading in C++ C++ Maximum Index Problem C++ find missing in the second array C++ Program to find the product array puzzle C++ Program To Find Largest Subarray With 0 Sum C++ Program To Move All Zeros To The End Of The Array C++ Program to find the element that occurs once C++ Program to find the largest number formed from an array Constructor Vs Destructor C++ Namespaces C++ OOPs Concept C++ Static C++ Structs C++ Try-Catch C++ User Defined Exceptions C++ Virtual Destructor C++ vs C# Malloc() and new in C++ Palindrome Number Program in C++ Snake Code in C++ Splitting a string in C++ Structure Vs Class in C++ Virtual Function Vs Pure Virtual Function C++ Bidirectional Iterators C++ Forward Iterators C++ Iterators C++ Output Iterators C++ Range-based For Loop Converting string into integer in C++ LCM Program in C++ Type conversion in C++ Add two numbers using the function in C++ Advantage and disadvantage friend function C++ Armstrong Number Program in C++ ATM machine program in C++ using functions Binary to Decimal in C++ Bit Manipulation in C++ C++ Constructor C++ Dijkstra Algorithm Using the Priority Queue C++ int into String C++ Signal Handling Decimal to Binary in C++ Decimal to Hexadecimal in C++ Decimal to Octal in C++ Factorial Program in C++ Function in C++ Hexadecimal to Decimal in C++ Octal to Decimal in C++ Reverse a Number in C++ Structure Vs Class in C++ C++ Forward Iterators C++ Output Iterators C++ Prime number program Char Array to String in C++ Constructor Overloading in C++ Default arguments in C++ Different Ways to Compare Strings in C++ Dynamic Binding in C++ Program to convert infix to postfix expression in C++ SET Data Structure in C++ Upcasting and Downcasting in C++ Reverse an Array in C++ Fast Input and Output in C++ Delete Operator in C++ Copy elision in C++ C++ Date and Time C++ Bitwise XOR Operator Array of sets in C++ Binary Operator Overloading in C++ Binary Search in C++ Implementing the sets without C++ STL containers Scope Resolution Operator in C++ Smart pointers in C++ Types of polymorphism in C++

C++ File Handling

File handling is a mechanism that manipulates the data stored in files. File handling store output data from the program to external file and read file data to the program. There are two types of communication takes place program.
  1. Data transfer between the console unit and program.
  2. Data transfer between program and disk file.

C++ Standard File Handling Class

C++ contains a set of library classes that handle the file handling methods. These classes include:
  1. ifstream: this header file is used to read input file stream from the file using istream.
  2. ofstream: this header file is used to write output file stream into the file using ostream.
  3. fstream: this header file is used for both input and output operation and inherits all the function of istream and ostream thorough iostream.
The above classes are derived from fstreambase and from the corresponding iostream class.

Input and Output Stream

The stream that supplies data from file to program is known as input stream. Input stream is used to read the file into program. The stream that supplies data from the program to file is known as an output stream. The output stream is used to write from the program into file. C++ file handling header files contain several functions for different operations.
Function Description
open() To create a new file as well as open an existing file
close() To close an existing file
read() Read data from the file
write() Write data into the file
get() Read a single character from a file
put() Write a single character into a file

C++ File Handling Mode Parameter

Mode parameter in the file handling defines the specific purpose for which the file is opened. The mode parameter is always passed as the second parameter in the file handling methods. These modes are:
Mode Description
Ios::in Open file in read mode
Ios::out Open file in write mode
Ios::app Append to end of file
Ios::ate Go to end of file on opening
Ios::trunk Delete the content of the file if it exits

C++ File Handling open() Function

A file must be opened before doing any manipulation over it. The open() function is used to open a file either for read from or write into a file. Syntax
file-stream-class   file-stream-object;  
file-stream-object.open("filename");
Example
ofstream  outfile;        
outfile . open ("employee.txt");

C++ File Handling open() Function Example

#include <iostream>  
#include <fstream>  
using namespace std;  
int main () {  
  ofstream myfile;  
// open file employee.txt  
  myfile.open ("D:/Ashutosh/C++ Tutorial/C++ tutorial/employee.txt");// 
check file location  
  if(myfile.is_open()){  
    cout<<"File is open"<<endl;  
    myfile << "Writing into a file.\n";  
    myfile.close();  
  }  
  else{  
    cout<<"Error in file opening"<<endl;  
  }  
  return 0;  
}
Output: 



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