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C++
  • 1. C++ Basics
    • 1.1 Input, Output, and Program Structure
      • 1.1.1 Welcome to Data Structures in C++
      • 1.1.2 Hello World
      • 1.1.3 Input and Output
      • 1.1.4 getline and cin
      • 1.1.5 Program Structure
    • 1.2 Basic Data Types
      • 1.2.1 Basic Data Types
        • 1.2.1.1 Differences between C++ and Java Data Types and Variables
      • 1.2.2 Strings and Characters
      • 1.2.3 Numbers
      • 1.2.4 Booleans
    • 1.3 Conditional Statements
      • 1.3.1 Conditional Statements
      • 1.3.2 Basic If/Else Statements
      • 1.3.3 Comparing Strings
      • 1.3.4 Logical Operators
    • 1.4 Loops
      • 1.4.1 Loops
      • 1.4.2 For Loops
      • 1.4.3 While Loops
      • 1.4.4 Searching a String
    • 1.5 Functions in C++
      • 1.5.1 Functions in C++
      • 1.5.2 Defining and Calling Functions
      • 1.5.3 Passing by Reference vs Value
      • 1.5.4 Function Prototypes
  • 2. Going Beyond the Basics
    • 2.1 Vector Basics
      • 2.1.1 Vector Basics
      • 2.1.2 Creating and Accessing Vectors
      • 2.1.3 Inserting into a Vector
      • 2.1.4 Looping Through a Vector
    • 2.2 Function Default Values
      • 2.2.1 Function Default Values
      • 2.2.2 Default Values
      • 2.2.3 Default Values with a Prototype
      • 2.2.4 Example: Splitting a String
    • 2.3 Structs
      • 2.3.1 Structs
      • 2.3.2 Defining and Accessing Structs
      • 2.3.3 Using Structs: Line Length
    • 2.4 File Input/Output
      • 2.4.1 File Input/Output
      • 2.4.2 Reading in a File
      • 2.4.3 Processing a File
      • 2.4.4 Writing to a File
      • 2.4.5 Creating an Input Stream from a String
    • 2.5 Error Handling
      • 2.5.1 Error Handling
      • 2.5.2 Validating a Number
      • 2.5.3 Validating a Vector Index
      • 2.5.4 Throwing Other Values
  • 3. Libraries
    • 3.1 Header Files
      • 3.1.1 Header Files
      • 3.1.2 Header File
      • 3.1.3 Header and Implementation File
      • 3.1.4 Safer Header
    • 3.2 Using Libraries
      • 3.2.1 Using a Utilities Library
      • 3.2.2 The Util Library
  • 4. 2D Vectors, Stacks, and Queues
    • 4.1 2D Vectors
      • 4.1.1 2D Vectors
      • 4.1.2 The 2D Vector
      • 4.1.3 Creating a 2D Vector
    • 4.3 Stacks
      • 4.3.1 Stacks
      • 4.3.2 Basic Stack
      • 4.3.3 Stack Example: Reverse a String
    • 4.5 Queues
      • 4.5.1 Queues
      • 4.5.2 Basic Queues
      • 4.5.3 Queue Example: Next in Line
  • 5. Sets and Maps
    • 5.1 Pairs and Iterators
      • 5.1.1 Pairs and Iterators
      • 5.1.2 Pairs
      • 5.1.3 Iterators
    • 5.3 Sets
      • 5.3.1 Sets
      • 5.3.2 Basic Sets
      • 5.3.3 Iterating Through a Set
      • 5.3.4 Sets of Struct Values
    • 5.4 Maps
      • 5.4.1 Maps
      • 5.4.2 Map Basics
      • 5.4.3 Iterating Through a Map
      • 5.4.4 Updating Maps
  • 6. Recursion
    • 6.1 Functional Recursion
      • 6.1.1 Functional Recursion
      • 6.1.2 Basic Recursive Problem: Exponential
      • 6.1.3 Recursion Example: Reverse String
      • 6.1.4 Recursion Example: Make Sum
    • 6.2 Procedural Recursion
      • 6.2.1 Procedural Recursion
      • 6.2.2 Print Binary
      • 6.2.3 Print Permutations
      • 6.2.4 Depth vs Breadth Search
  • 7. Pointers, Linked Lists, and Graphs
    • 7.1 Pointers
      • 7.1.1 Pointers
      • 7.1.2 Assigning and Updating Pointers
      • 7.1.3 Pointers and Functions
      • 7.1.4 Pointers and Data Structures
    • 7.2 Linked Lists
      • 7.2.1 Linked Lists
      • 7.2.2 Basic Linked List
      • 7.2.3 Linked List and Recursion
      • 7.2.4 Example: Sorted Phone Book
      • 7.2.5 Doubly Linked List
    • 7.3 Graphs
      • 7.3.1 Graphs
      • 7.3.2 Basic Example: Breadth First Search
      • 7.3.3 Application: Connecting Cities
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  • Creating the Output File Stream
  • Streaming To the Output File
  • Try This Example
  1. 2. Going Beyond the Basics
  2. 2.4 File Input/Output

2.4.4 Writing to a File

Previous2.4.3 Processing a FileNext2.4.5 Creating an Input Stream from a String

Last updated 1 year ago

Just like reading in from a file is similar to reading in from the console, writing to a file is similar to writing to the console. To output to a file, you will open a file as an output file stream and then stream into the file the same way you would stream to the console.

Creating the Output File Stream

As mentioned earlier in the lesson, the fstream library is used for both input and output files. To output to a file, you will first include the fstream library.

#include <fstream>

As you did with file input, you are going to create an output file stream variable and then open the file name that you want. If the file does not already exist, it will be created. If it does exist, it will be overwritten.

ofstream out;
out.open("output.txt");

Streaming To the Output File

Once the output file stream has been created, streaming to the file is the same as streaming to the console, just replacing cout with the output file stream. For example, if you use the out variable created above, you can stream Hello World to the file like this:

out << "Hello World" << endl;

When you are finished with your output, you can close the file using the close function.

out.close();

Try This Example