C++遍历算法

Posted 2021-10-02 爱吃香蕉的猴子0000

Hello, 大家好，我是爱吃香蕉的猴子，写写C++的遍历

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#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

//transform 将一个容器的元素 搬运 到另一个容器中
struct MyPlus{
	int operator()(int val){
		return val + 100;
	}
};

void MyPrint(int val){
	cout << val << " ";
}
void test01(){

	vector<int> v1;
	vector<int> v2;
	

	for (int i = 0; i < 10;i++){
		v1.push_back(i);
	}

	v2.resize(v1.size()); //开辟空间

	transform(v1.begin(), v1.end(), v2.begin(), MyPlus());
	for_each(v2.begin(), v2.end(), MyPrint);
	cout << endl;
}

//常用的查找算法
void test02(){
	
	vector<int> v1;
	for (int i = 0; i < 10; i++){
		v1.push_back(i);
	}

	vector<int>::iterator ret = find(v1.begin(), v1.end(), 5);
	if (ret == v1.end()){
		cout << "么有找到!" << endl;
	}
	else{
		cout << "找到了:" << *ret << endl;
	}
}

class Person{
public:
	Person(int age, int id) :age(age), id(id){}
	bool operator==(const Person& p) const{
		return p.id == this->id && p.age == this->age;
	}
public:
	int id;
	int age;
};

void test03(){
	
	vector<Person> v1;

	Person p1(10, 20), p2(20, 30);

	v1.push_back(p1);
	v1.push_back(p2);

	vector<Person>::iterator ret =  find(v1.begin(), v1.end(), p1);
	if (ret == v1.end()){
		cout << "么有找到!" << endl;
	}
	else{
		cout << "找到了:" << endl;
	}

}

//binary_search 二分查找法
bool MySearch(int val){
	return val > 5;
}
bool MySearch2(int val){
	return val > 5;
}
void test04(){
	
	vector<int> v1;
	for (int i = 0; i < 10; i++){
		v1.push_back(i);
	}
	v1.push_back(9);

	bool ret =binary_search(v1.begin(), v1.end(), 5);
	if (ret){
		cout << "找到！" << endl;
	}else{
		cout << "没有找到!" << endl;
	}

	vector<int>::iterator it =  adjacent_find(v1.begin(), v1.end());
	if (it != v1.end()){
		cout << "找到相邻重复元素:" << *it <<  endl;
	}
	else{
		cout << "没有找打相邻重复元素" << endl;
	}

	//find_f 会根据我们的条件(函数) ，返回第一个满足条件的元素的迭代器
	it =  find_if(v1.begin(), v1.end(), MySearch);
	if (it != v1.end()){
		cout << "找到:" << *it << endl;
	}
	else{
		cout << "没有找到" << endl;
	}

	//count count_if
	int num = count(v1.begin(), v1.end(), 9);
	cout << "9出现的次数:" << num << endl;
	num = count_if(v1.begin(), v1.end(), MySearch2);
	cout << "大于5的个数：" << num << endl;

}



int main(void){
	
	//test01();
	//test02();
	//test03();
	test04();


	return 0;
}

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                             Code的搬运工V1.0