#include <iostream>
using namespace std;
int main() {
	cout << "Hello World!" << endl;
}

#include <iostream>
using namespace std;
int main() {

}

#include <iostream>
using namespace std;
int main() 
{

}

int a;

int a = 2, b = 0;
a = a + 5 * 6 / 7 % 3;
b += a;
a += b;
cout << a << " " << b <<  endl;

char c = 'a';
cout << c + 1 << endl; //b

if (條件成立) {
    //執行程式
} else if (上面不成立時下面成立) {
    //...
} else {
    //前面都不符合時
}

int a = 5, b = 5;
if (a == b) {
    cout << "7122" << endl;
}

while (條件成立) {
    //做事
}

int a = 5;
while (a > 0) {
	cout << a << endl;
    a = a - 1;
}

for (起始條件; 判斷條件; 更新動作) {
	//做事
}

for (int i = 0;i < 10;i++) {
	cout << i * i << endl;
}

for (int i = 0;i < 10;i++) {
	for (int j = 0;j < 10;j++) {
    	cout << i * 10 + j << endl;
    }
}

int n;
cin >>ｎ;
for (int i = 0;i < n;i++) {

}

#include <bits/stdc++.h>
int main(){
    bool num1 ;
    bool num2 ;
    bool num3 ;
    bool num4 ;
    bool num5 ;
}

#include <bits/stdc++.h>
int main(){
    bool num[31] ;
}

#include <bits/stdc++.h>
int main(){
    bool num[31] ;
    num[3] = true ;
}

#include <bits/stdc++.h>
int main(){
    int amount ;
    std::cin >> amount ;
    std::vector<bool> num ;
    num.reserve(amount) ;
}

#include <bits/stdc++.h>
int main(){
    int a_list[5][7] ; //我包2層
    int b_list[7][12][2] ; //我包3層
}
// 記得，陣列的每一格都要長一樣!

int b_list[7][12][2] ;

#include <bits/stdc++.h>
int main(){
    float a ;
    std::cin >> a ;
    std::cout << 1.0/a ; 
}

float rev(float x){
    return 1.0/x ;
}

//↓ 每個函式都要告訴電腦，他會傳哪種資料回來
int main(/* 函式應該知道的東西，叫參數 */){
    //函式的內容
    return 0 ;
    //每個函式最後都要return
}
//example
bool big(int a, int b){
    if (a > b) return true ;
    else return false ;
}

#include <bits/stdc++.h>
bool big(int a, int b){
    if (a > b) return true ;
    else return false ;
}
int main(){
    int x = 5, y = 7 ;
    cout << big(x,y) ; //false 
    //就這麼簡單!
}

int f[100]{1,1} ;
for(int i = 2 ; i <= n ; i++){
    f[i] = f[i-1] + f[i-2] ;
}

char c='a'
//字元以單引號' '夾住

char str[20]="Hello, world!";
//字串用雙引號" "夾住
cout<<str[4];
// o

#include<cstring>
string s="Hello, world!";
cout<<s[4];
// o

string s;
cin>>s;
cout<<s<<endl;
// input: Hello, world!
// output: Hello,

getline(cin,s);
cout<<s<<endl;
// input: Hello, world!
// output: Hello, world!

int main(){
    string s,tmp;
    getline(cin,s);
    stringstream ss(s);
    while(ss>>tmp){
        cout<<tmp<<endl;
    }
    return 0;
}

void swap(int x,int y){
    int tmp=x;
    x=y;
    y=tmp;
}
int main(){
    int x,y;
    cin>>x>>y;
    swap(x,y);
    cout<<x<<" "<<y<<endl;
}

int x = 3; //一個整數變數
int *p = &x;
// int *p: 整數型別的指標
// &x: 取x變數的記憶體位址
int* p; //也可以這樣
int *a, *b; //a,b都是指標
int* a, b; //只有a是指標

int x = 3; //一個整數變數
int *p = &x;
// int *p: 整數型別的指標
// &x: 取x變數的記憶體位址
cout<<(*p)<<endl;
// *p: 該記憶體位址儲存的值
// (其實就是x)

void swap(int *x,int *y){
    int tmp=*x;
    *x=*y;
    *y=tmp;
}
int main(){
    int x,y;
    cin>>x>>y;
    swap(&x,&y);
    cout<<x<<" "<<y<<endl;
}

void swap(int &x,int &y){
    int tmp=x;
    x=y;
    y=tmp;
}
int main(){
    int x,y;
    cin>>x>>y;
    swap(x,y);
    cout<<x<<" "<<y<<endl;
}

void print_arr(int* x,int cnt){
    for(int i=0;i<cnt;i++){
    	cout<<*(x+i)<<endl;
    }
}

struct node{
    int val;
    node* next;
    node(int v){
        val=v;
    }
};
node *root, *nd = new node(7122);
root->next = nd;

struct score{
    int math;
    int eng;
    bool pretend_weak;
};

struct score{
    int math;
    int eng;
    bool pretend_weak;
};
int main(){
    score myscore;
    myscore.math=71;
    myscore.eng=22;
}

struct score{
    int math;
    int eng;
    bool pretend_weak;
    score(int m,int e){
        math=m;
        eng=e;
        if(math<60||eng<60){
            pretend_weak=true;
        }
        else{
            pretend_weak=false;
        }
    }
};
int main(){
    score myscore=score(87,78);
    score yourscore=score(71,22);
    cout<<myscore.pretend_weak<<endl; //false
    cout<<yourscore.pretend_weak<<endl; //true
}

struct node{
    int val;
    node* next;
    node(int v){
        val=v;
    }
};
node *root, *nd = new node(7122);
root->next = nd;
cout<<root->next->val<<endl; //7122