Relocating Declarations Can Enhance Performance

On some occasions, the performance boost that can result from moving declarations is quite considerable. Consider this example:

   void use()  {    string  s1;    if (condition == false){      return; //s1 was not needed    }       s1 = "hello";    // s1 used only here    return;   }

The local object s1 is unconditionally constructed and destroyed in use(), even if it is not used at all. As you can see, when the condition in the if-statement is false, the unnecessary construction and destruction of s1 are still unavoidable. Nevertheless, with a little help from the programmer, the unnecessary construction and destruction of s1 can be eliminated. All that is required is to relocate the declaration of s1 to the point where it is actually used:

   void use(){    if (condition == false){      return;     }       string  s1; //moved from the block's beginning    //use s1 here    return;   }

Consequently, the object s1 is constructed only when it is really needed. When it is not needed, s1 is neither constructed nor destroyed. Thus, simply by moving the declaration of s1, you eliminate two unnecessary member function calls.

Share the Post:
Share on facebook
Share on twitter
Share on linkedin

Overview

The Latest

microsoft careers

Top Careers at Microsoft

Microsoft has gained its position as one of the top companies in the world, and Microsoft careers are flourishing. This multinational company is efficiently developing popular software and computers with other consumer electronics. It is a dream come true for so many people to acquire a high paid, high-prestige job

your company's audio

4 Areas of Your Company Where Your Audio Really Matters

Your company probably relies on audio more than you realize. Whether you’re creating a spoken text message to a colleague or giving a speech, you want your audio to shine. Otherwise, you could cause avoidable friction points and potentially hurt your brand reputation. For example, let’s say you create a

chrome os developer mode

How to Turn on Chrome OS Developer Mode

Google’s Chrome OS is a popular operating system that is widely used on Chromebooks and other devices. While it is designed to be simple and user-friendly, there are times when users may want to access additional features and functionality. One way to do this is by turning on Chrome OS