C++ Buffers

In C++, a buffer is a memory space for temporarily storing data before processing, writing to a file, or sending it over a network.

Buffers serve as intermediaries, facilitating seamless data transfer within your program and between external devices.

Importance of Buffer


Buffers help reduce the overhead of frequent I/O operations. Instead of reading or writing data one byte at a time (which can be slow), you can work with larger chunks of data stored in a buffer.

Minimizing I/O Calls

Buffers minimize the number of read and write operations, which are typically more time-consuming than working with data in memory.

Data Consistency

Buffers ensure that data is read or written consistently, reducing the likelihood of errors and improving the reliability of your code.

Optimizing Resources

Buffers allow your program to read or write data in larger blocks, making better use of system resources.

Create a Buffer

We can create a buffer in C++ simply by allocating memory:

char *buffer = new char buffer_name[buffer_size]


  • *buffer - pointer that points to the address of the buffer
  • buffer_name - name of the buffer
  • buffer_size - size of the buffer

We can also use buffers of other types such as int or double. However, char buffers are the most commonly used.

Note: We must always delete a buffer once we are done with it to free up space for future use. We can do this using delete[]

Example: Create a Buffer

#include <iostream>
using namespace std;

int main() {

// define the buffer size const int buffer_size = 1024; // declare a character buffer char *buffer = new char[buffer_size];
// prompt the user for input cout << "Enter a line of text: "; // read data into the buffer cin.getline(buffer, buffer_size); // display the content read from the buffer cout << "You entered: " << buffer;
// deallocate the dynamically allocated memory delete[] buffer;
return 0; }


Enter a line of text: 12
You entered: 12

Here, we have created a buffer to store the data inserted by the user.

char *buffer = new char[buffer_size];

Notice that we've defined the buffer size before creating the buffer:

const int buffer_size = 1024;

This is because we need to pass the buffer size as an argument to signify the delimiter for the getline() function:

// read data into the buffer
cin.getline(buffer, buffer_size);

Note: We have used cin.getline(buffer, buffer_size); instead of getline(cin, buffer); because buffer is a character pointer, not a string variable.

Once we were done with our buffer, we deleted it immediately.

Types of Buffers

In C++, there are several types of buffers, each serving a specific purpose:

Stream Buffers

They are associated with input and output streams like cin and cout. Stream buffers are used to store data temporarily before it is displayed on the screen or written to a file.

File Buffers

They are used when reading from or writing to files. File buffers help in efficiently managing data transfer between your program and the file system.

Character Buffers

Character arrays, often referred to as C-style strings, can be considered simple buffers used to store sequences of characters.

Custom Buffers

You can also create your own custom buffers using arrays or data structures like std::vector or std::array to suit your specific needs.

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