Another Technique for Assigning a Zero Value to All Members of a Struct

Another Technique for Assigning a Zero Value to All Members of a Struct

In addition to the technique described in tip #453, “Assigning A Zero Value to All Members of A Struct”, C++ (but not C) offers another method of assigning all the members of a struct to binary zeros at once. This method applies to small structs that occupy up to 8 bytes (10 bytes on platforms that support type long double).

This technique makes use of an anonymous union, which is an ordinary union except that it has no tag name and no instance name. The trick is to create an anonymous union that contains an instance of that struct and another built-in data type that occupies exactly the same size as that struct:

   struct Date  {    char day;    char month;    short year;  }; // Date occupies 4 bytes  int main()  {    union  //anonymous    {      Date d;      int num;    };  //use d = 13; d.month = 4; d.year = 2000; //now assign all members of d to binary zeros through num    num = 0;  }

Inside main(), the programmer defined an anonymous union that contains a Date object and an int. After filling d’s data members with values, the program resets these data members by assigning the value of 0 to num. This assignment actually resets all the bits of d to zeros, because d and num are stored at the same memory address and occupy the same size. Note that you use the members of an anonymous union directly, as if they were declared outside of a union. This convenience of referring to the union’s members directly cannot be achieved when using a named union.

Share the Post:
XDR solutions

The Benefits of Using XDR Solutions

Cybercriminals constantly adapt their strategies, developing newer, more powerful, and intelligent ways to attack your network. Since security professionals must innovate as well, more conventional endpoint detection solutions have evolved

AI is revolutionizing fraud detection

How AI is Revolutionizing Fraud Detection

Artificial intelligence – commonly known as AI – means a form of technology with multiple uses. As a result, it has become extremely valuable to a number of businesses across

AI innovation

Companies Leading AI Innovation in 2023

Artificial intelligence (AI) has been transforming industries and revolutionizing business operations. AI’s potential to enhance efficiency and productivity has become crucial to many businesses. As we move into 2023, several

data fivetran pricing

Fivetran Pricing Explained

One of the biggest trends of the 21st century is the massive surge in analytics. Analytics is the process of utilizing data to drive future decision-making. With so much of

kubernetes logging

Kubernetes Logging: What You Need to Know

Kubernetes from Google is one of the most popular open-source and free container management solutions made to make managing and deploying applications easier. It has a solid architecture that makes

ransomware cyber attack

Why Is Ransomware Such a Major Threat?

One of the most significant cyber threats faced by modern organizations is a ransomware attack. Ransomware attacks have grown in both sophistication and frequency over the past few years, forcing

data dictionary

Tools You Need to Make a Data Dictionary

Data dictionaries are crucial for organizations of all sizes that deal with large amounts of data. they are centralized repositories of all the data in organizations, including metadata such as