How to use C++ 's StringBuilder to improve performance

Today, I will talk to you about how to use C++ 's StringBuilder to improve performance. Many people may not understand it very well. In order to make you understand better, the editor has summarized the following for you. I hope you can get something from this article.

Introduction

Clients often call to complain that your program is as slow as a snail. You start to check for possible doubts: file IO, database access speed, and even check web services. But all these possible doubts are normal and there is no problem at all.

You use the most convenient performance analysis tool to analyze and find that the bottleneck lies in a small function that writes a long list of strings into a file.

You have optimized this function as follows: concatenate all small strings into a long string, perform a file write operation, and avoid thousands of small string write operations.

This optimization is only half right.

You first test the speed of writing files with large strings and find that they are as fast as lightning. Then you test the speed of all the strings concatenated.

For years.

What's going on? How will you overcome this problem?

You may know that. Net programmers can use StringBuilder to solve this problem. This is also the starting point of this article.

Background

If you google "C++ StringBuilder", you will get a lot of answers. Some will suggest using std::accumulate, which can accomplish almost everything you want to achieve:

# include / / for std::cout, std::endl # include / / for std::string # include / / for std::vector # include / / for std::accumulate int main () {using namespace std; vector vec = {"hello", "", "world"}; string s = accumulate (vec.begin (), vec.end (), s); cout