#include<iostream>
using namespace std;
//仿函数在使用时可以像普通函数那样调用，可以有参数和返回值
class add {
public:
  int operator()(const int value1, const int value2)
  {
  return value1 + value2;
  }
};
class sub {
public:
  int operator()(const int value1, const int value2)
  {
  return value1 - value2;
  }
};
class mul {
public:
  double operator()(const double value1,const double value2)
  {
  return value1 * value2;
  }
};
void text()
{
  add ad;
  cout << "相加：" << ad(10, 20) << endl;
  sub sb;
  cout << "相减：" << sb(10, 20) << endl;
  mul ml;
  cout << "相乘：" << ml(5.5,7) << endl;
}
int main()
{
  text();
}

#include<iostream>
using namespace std;
class print {
public:
  void operator()(const int value1,const int value2)//仿函数不同于普通函数的概念，它可以有自己的状态
  {
  cout << "相加：" << value1 + value2 << endl;
  cout << "相减：" << value1 - value2 << endl;
  cout << "相乘：" << value1 * value2 << endl;
  }
};
void text()
{
  print pt;
  pt(10,20);
}
int main()
{
  text();
}

#include<iostream>
using namespace std;
class print {
public:
  void operator()(const int value1, const int value2)
  {
  cout << "相加：" << value1 + value2 << endl;
  cout << "相减：" << value1 - value2 << endl;
  cout << "相乘：" << value1 * value2 << endl;
  }
};
void scanf(print &pt)//仿函数可以作为参数传递
{
  pt(10,20);
}
void text()
{
  print pt;
  scanf(pt);
}
int main()
{
  text();
}

#include<iostream>
#include<algorithm>  //STL算法头文件定义
#include<vector>
using namespace std;
class unitary {
public:
  bool operator()(const int value)  //一元仿函数
  {
  return value == 20;
  }
};
void text()
{
  vector<int>v;
  for (int i = 1, j = 10; i <= 10; i++, j += 10)
  {
  v.push_back(j);
  }
  //10 20 30 40 50 60 70 80 90 100
  vector<int>::iterator p = find_if(v.begin(), v.end(), unitary());  
  //利用find_if这个算法，在一元仿函数中去判断vector容器中是否有元素20
  if (p == v.end())
  cout << "未找到" << endl;
  else
  cout << "从vector容器中找到了值为20的元素" << endl;
}
int main()
{
  text();
}

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
void printvector(vector<int>&v)
{
  for (vector<int>::iterator i = v.begin(); i != v.end(); i++)
  {
  cout << *i<<" ";
  }
  cout << endl;
}
class compare {
public:
  bool operator()(const int value1,const int value2)  //二元仿函数
  {
  return value1 > value2;
  }
};
void text()
{
  vector<int>v;
  v.push_back(45);
  v.push_back(10);
  v.push_back(9);
  v.push_back(67);
  v.push_back(35);
  //45 10 9 67 35
  cout << "从小到大排序：";
  sort(v.begin(), v.end());
  //9 10 35 45 67
  printvector(v);
  cout << "从大到小排序：";
  sort(v.begin(), v.end(), compare());
  //67 45 35 10 9
  printvector(v);
}
int main()
{
  text();
}

#include<iostream>
#include<functional>  //内建仿函数头文件定义
using namespace std;
void text()
{
  //相加仿函数
  plus<int>p;
  cout << "相加：" << p(10, 20) << endl;
  //相减仿函数
  minus<float>mi;
  cout << "相减：" << mi(3.18,2.90) << endl;
  //乘法仿函数
  multiplies<double>mu;
  cout << "相乘：" << mu(9.19, 3.14) << endl;
  //除法仿函数
  divides<double>di;
  cout << "相除：" << di(25.75, 3.15) << endl;
  //取模仿函数
  modulus<int>mo;
  cout << "取模：" << mo(9,4) << endl;
  //取反仿函数
  negate<int>n;
  cout << "取反：" << n(1) << endl;
}
int main()
{
  text();
}

#include<iostream>
#include<algorithm>
#include<functional>
#include<vector>
using namespace std;
void printvector(vector<int>&v)
{
  for (vector<int>::iterator i = v.begin(); i != v.end(); i++)
  {
  cout << *i<<" ";
  }
  cout << endl;
}
void text()
{
  vector<int>v;
  cout << "请向vector容器中输入元素：" << endl;;
  for (int i = 1; i <= 10; i++)
  {
  int elem; cin>>elem;
  v.push_back(elem);
  }
  //常用关系仿函数
  //大于=降序
  sort(v.begin(),v.end(),greater<int>());
  printvector(v);
  //小于=升序
  sort(v.begin(), v.end(), less<int>());
  printvector(v);
}
int main()
{
  text();
}

#include<iostream>
#include<vector>
#include<functional>
#include<algorithm>
using namespace std;
void printvector(vector<bool>&v)
{
  for (vector<bool>::iterator i = v.begin(); i != v.end(); i++)
  {
  cout << *i<<" ";
  }
  cout << endl;
}
void text()
{
  vector<bool>v;
  v.push_back(true);
  v.push_back(false);
  cout << "初始状态：" << endl;
  printvector(v);
  vector<bool>v1;
  v1.resize(v.size());
  transform(v.begin(), v.end(), v1.begin(), logical_not<bool>());
  cout << "逻辑非后的状态：" << endl;
  printvector(v1);
}
int main()
{
  text();
}