---
title: "2.6 Using std::endl"
description: "The `std::endl` manipulator inserts a newline character into the output stream and immediately flushes the stream buffer. Flushing ensures that all buffered output is written to the destination before the program continues. Although `std::endl` is convenient, it is generally used…"
url: "https://edcret.in/docs/cpp-programming/input-and-output-cplusplus/2-6-using-stdendl/"
updated: "2026-07-28"
category: C++ Programming / Input and Output
---

# 2.6 Using std::endl

The `std::endl` manipulator inserts a newline character into the output stream and immediately flushes the stream buffer. Flushing ensures that all buffered output is written to the destination before the program continues.

Although `std::endl` is convenient, it is generally used only when flushing the output stream is required. For ordinary line breaks, the newline character (`'\n'`) is usually more efficient because it does not automatically flush the stream.

## Source Code

```
#include <iostream>

int main()
{
    std::cout << "First Line" << std::endl;
    std::cout << "Second Line" << std::endl;

    return 0;
}
```

## Output

```
First Line
Second Line
```

## Explanation

- `std::endl` is a stream manipulator defined in the `<iostream>` library.
- It inserts a newline character into the output stream.
- After inserting the newline, `std::endl` flushes the output buffer immediately.
- Flushing forces any buffered output to be written to the output device before the program continues.
- Frequent use of `std::endl` may reduce performance because flushing the stream is relatively expensive.
- When only a new line is needed, using `'\n'` is generally more efficient.
- `return 0;` terminates the program successfully.