輸入輸出

cin cout getline stringstream fixed<<setprecision(n)

cin輸入 cout輸出

/*
 * zerojudge
 * a001. 哈囉
 * C++
 * AC (3ms, 320KB)
*/
#include <bits/stdc++.h>
using namespace std;

int main(){
    string s;
    cin >> s;
    cout << "hello, " << s << endl;
    return 0;
}

cin EOF

/*
 * zerojudge
 * a004. 文文的求婚
 * C++
 * AC (8ms, 312KB)
*/
#include <bits/stdc++.h>
using namespace std;

int main(){
    int n;
    while(cin >> n){
        if( (n%4==0 && n%100!=0) || n%400==0){
            cout << "閏年" << endl;
        }else{
            cout << "平年" << endl;
        }
    }
    return 0;
}

getline 整行輸入

/*
 * zerojudge
 * a011. 00494 - Kindergarten Counting Game
 * C++
 * AC (2ms, 312KB)
*/
#include<bits/stdc++.h>
using namespace std;

bool f(char c){
	if( c<='z' && c>='a' || c<='Z' && c>='A' ){
		return 1;
	}else{
		return 0;
	}
}


int main(){
	string s;
	while(getline(cin,s)){
		int sum=0;
		int i=0;
		bool isEn = false;
		for(;i<s.size();i++){
			if(isEn){
				if(f(s[i])==0){
					isEn=0;
				}
			}else{
				if(f(s[i])==1){
					sum+=1;
					isEn=1;
				}
			}
		}
		cout << sum << endl;
	}
}

stringsteam 把有空格字串當 cin

/*
 * zerojudge
 * e997. 升旗典禮抽背課文
*/
#include<bits/stdc++.h>
using namespace std;

int main(){
    string line;
    getline(cin,line);
    stringstream ss(line);
    vector<string>v;
    string x;
    int cnt = 0;
    while(ss >> x){
        v.push_back(x);
        cnt+=1;
    }
    int c;
    cin >> c;
    cout << v[cnt-c] << endl;
}

小數點控制

/*
 * zerojudge
 * a410. 解方程
 * C++
 * AC (2ms, 328KB)
*/
#include<bits/stdc++.h>
using namespace std;

int main(){
	float a,b,c,d,e,f;
	cin >> a >> b >> c >> d >> e >> f;
	//
	if(a*e==d*b){
		if(a*f==c*d){
			cout << "Too many\n";
		}
		else{
			cout << "No answer\n";
		}
	}
	else{
		float x=(c*e-b*f)/(a*e-b*d);
		float y=(c*d-a*f)/(b*d-a*e);
		//
		cout << "x=" << fixed << setprecision(2) << x << endl;
		cout << "y=" << fixed << setprecision(2) << y << endl;
	}
}

如果cin後面要接getline，記得要加cin.ignore();

cin >> input;
cin.ignore();
getline(cin,s);