c++谓词的使用，仿函数在sort的表达形式

#include <iostream>
#include <algorithm>
using namespace std;
#include <string>
#include <vector>
#include <functional>

//一元谓词
class GreaterFive {
public:
	bool operator()(int val) {
		return val > 5;
	}
};

//二元谓词
class MyCompare {
public:
	bool operator()(int v1, int v2) {
		return v1 > v2;
	}
};

void test601() {
	vector<int> v;
	for (int i = 0; i < 10; i++) {
		v.push_back(i);
	}

	vector<int>::iterator it = find_if(v.begin(), v.end(), GreaterFive());
	if (it == v.end())
		cout << "no find" << endl;
	else
		cout << "find this num:" << *it << endl;

	sort(v.begin(), v.end());
	//使用函数对象 改变算法策略
	sort(v.begin(), v.end(),MyCompare());

	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << "  ";
	}
	cout << endl;
}

void test602() {
	//一元仿函数  struct / class   T    negate
	negate<int>n;
	cout << n(50) << endl;

	cout << negate<double>()(50.2) << endl;

	//er yuan 
	plus<int> p;
	cout << p(24, 36) << endl;

	cout << greater<double>()(53, 33) << endl;

}

void printInt(vector<int> & v) {
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
		cout << *it << "  ";
	}
	cout << endl;
}

void test603() {
	vector<int> v;
	v.push_back(4);
	v.push_back(3);
	v.push_back(1);
	v.push_back(46);

	sort(v.begin(), v.end(), greater<int>());
	printInt(v);
	sort(v.begin(), v.end(), less<>());
	printInt(v);
	sort(v.begin(), v.end(), greater<>{});
	printInt(v);
}

int main() {
	//test601();
	//test602();
	test603();
	return 0;
}