Introduction

Method

1. insert(n) 把一個數字 n 放進集合
2. erase(n) 把某個數字 n 從集合中移除
3. count(n) 檢查某個數 n 是否有在集合中

Advantages and disadvantages

Advantages

操作很簡單
可以快速檢查裡面有沒有某個元素

Disadvantages

當 Set 裡面東西太多時會拖慢速度

Example

#include <iostream>
#include <set>
using namespace std;
int main(int argc, char *argv[]){
    set<int, greater<int> > mySet;
    
    mySet.insert(10);
    mySet.insert(20);
    mySet.insert(30);
    mySet.insert(40);
    mySet.insert(50);
 	
	cout << "10 " << mySet.count(10) << '\n'; // 1
	cout << "20 " << mySet.count(20) << '\n'; // 1
	cout << "30 " << mySet.count(30) << '\n'; // 1
	cout << "40 " << mySet.count(60) << '\n'; // 0
	mySet.erase(20);
	cout << "20 " << mySet.count(20) << '\n'; // 0
 
    return 0;
}
 
 

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set

Have a try

b050

Introduction

Tuple let you combine two or more value into one vaiable

Method

make_tuple
using namespace std;
tuple<double, char, string> get_student(int id)
{
    if (id == 0) return make_tuple(3.8, 'A', "Lisa Simpson");
    if (id == 1) return make_tuple(2.9, 'C', "Milhouse Van Houten");
    if (id == 2) return make_tuple(1.7, 'D', "Ralph Wiggum");
    throw invalid_argument("id");
}

Example

#include <iostream>
#include <tuple>
using namespace std;
int main(int argc, char *argv[]){
	// 1
	tuple<int, int, int> t1 = {1, 3, 4};
	cout << get<0>(t1) << '\n'; // 1
	cout << get<1>(t1) << '\n'; // 3
	cout << get<2>(t1) << '\n'; // 4
 
    return 0;
}

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tuple