Function Object Bases

To simplify the process of writing custom function objects, the Standard Library provides two classes that serve as base classes of such objects: std::unary_function and std::binary_function. Both are declared in the header . As the names suggest, unary_function serves as the base of function objects taking one argument and binary_function serves as the base of function objects taking two arguments. Here’s the definition of these base classes:

 template  struct unary_function { typedef Arg argument_type; typedef Res result_type;};template  struct binary_function { typedef Arg first_argument_type; typedef Arg2 second_argument_type; typedef Res result_type;};

These classes don’t provide any useful functionality. They are used to ensure that arguments and return values have uniform names. In the following example, a predicate (a function object returning bool) called is_vowel, which takes one argument, inherits from unary_function:

 template  class is_vowel: public unary_function{public: bool operator ()(T t) const {  if ((t=='a')||(t=='e')||(t=='i')||(t=='o')||(t=='u'))   return true;  return false; }};

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


The Latest

homes in the real estate industry

Exploring the Latest Tech Trends Impacting the Real Estate Industry

The real estate industry is changing thanks to the newest technological advancements. These new developments — from blockchain and AI to virtual reality and 3D printing — are poised to change how we buy and sell homes. Real estate brokers, buyers, sellers, wholesale real estate professionals, fix and flippers, and beyond may

man on floor with data

DevX Quick Guide to Data Ingestion

One of the biggest trends of the 21st century is the massive surge in internet usage. With major innovations such as smart technology, social media, and online shopping sites, the internet has become an essential part of everyday life for a large portion of the population. Due to this internet

payment via phone

7 Ways Technology Has Changed Traditional Payments

In today’s digital world, technology has changed how we make payments. From contactless cards to mobile wallets, it’s now easier to pay for goods and services without carrying cash or using a checkbook. This article will look at seven of the most significant ways technology has transformed traditional payment methods.