Built-in function object
4.3.1 Meaning of built-in function objects
Concept:
STL has some built-in function objects
classification:
Arithmetic functors
Relational functors
Logical functors
usage:
The usage of the objects generated by these functors is exactly the same as
that of general functions. To use built-in function objects, you need to introduce the header file #include
Arithmetic functor
Function description:
Realize four arithmetic operations.
Negate is a unary operation, and the others are binary operations.
Function prototype:
template<class T> T plus<T> //加法仿函数
template<class T> T minus<T> //减法仿函数
template<class T> T multiplies<T> //乘法仿函数
template<class T> T divides<T> //除法仿函数
template<class T> T modulus<T> //取模仿函数
template<class T> T negate<T> //取反仿函数
Code example:
#include<iostream>
#include<functional>
using namespace std;
//negate一元仿函数 取反仿函数
void test01()
{
negate<int>n;
cout << n(50) << endl;
}
//plus二元仿函数 加法
void test02()
{
plus<int>p;
cout << p(10, 20) << endl;
}
int main()
{
test01();
test02();
system("pause");
return 0;
}
Summary: When using the built-in functor object, you need to include the header file #include