C++ Weekly Tips 01 - "std::endl" vs "\n" which is faster

Today, we will discuss basic techniques in C++. It is the new line character. In C++ we have two ways to print out a new lines.

1. printf(“\n”);
2. using std::cout « std::endl;

The question is which one is faster? Answer: '\n' is significantly faster than std::endl in C++. Here’s why: \n is simply a newline character. It inserts a new line into the output stream without any additional operations. std::endl does two things:

1. Inserts a newline character.
2. Flushes the output buffer.

Flushing the output buffer forces the contents of the buffer to be written to the actual output device (like the console or a file). This operation can be quite expensive, especially if done frequently. In most cases, you don’t need to explicitly flush the output buffer. The buffer is automatically flushed when:

• The buffer is full.
• The program terminates.
• An input operation is performed (e.g., cin).

Therefore, using \n is generally the preferred choice for performance reasons. Only use std::endl if you specifically need to force a flush of the output buffer.

Example:

#include 
int main() {
    for (int i = 0; i < 1000000; ++i) {
        std::cout << "Hello, world!\n"; // Faster
        // std::cout << "Hello, world!" << std::endl; // Slower
    }
    return 0;
}

Use code with caution. In this example, using \n will result in significantly faster execution compared to using std::endl. Remember: While performance is important, readability and maintainability are also crucial factors. If you need to explicitly flush the output buffer for specific reasons, using std::endl is acceptable. However, in most cases, \n is the better choice.

Would you like to know more about output buffering or other performance optimization techniques? Follow me on social.