What is endl in C++?

In C++, endl is a manipulator used with output streams like std::cout to insert a newline character (\n) and flush the output buffer. It ensures that the output is immediately written to the console or file, which is particularly useful when dealing with buffered output.

Example of endl Usage:

#include <iostream>
using namespace std;

int main() {
    cout << "Hello" << endl;  // Outputs "Hello" followed by a newline
    cout << "World" << endl;  // Outputs "World" followed by a newline
    return 0;
}

Key Points:

• Newline: endl inserts a newline character (\n), moving the cursor to the next line.
• Buffer Flush: It also flushes the output buffer, meaning the content is immediately sent to the console or file. This is important in situations where you want to ensure that the output is not delayed, like when debugging.

endl vs \n:

• endl: Inserts a newline and flushes the buffer.
• \n: Only inserts a newline without flushing the buffer, making it more efficient for performance in scenarios where frequent flushing is not necessary.

In most cases, if you do not need to flush the buffer, using \n is preferred for performance reasons.

Sources:

• GeeksforGeeks: endl in C++
• cplusplus.com: Standard I/O Streams