This video, kindly made by Chris Roffey from Bebras UK, nicely demonstrates how to use the code editor/grader on this site:
All inputs should be read from standard in and outputs printed to standard out.
Students are permitted to have available up to 20 sides of custom notes/snippets (paper or digital) in addition to the standard documentation for their chosen language during the competition. One such example for python is this document, adapted with permission from Coding-Club Core Cards.
These examples all read a single integer and print double that number out.
Python:
num = int(input())
print(num * 2)
Java:
import java.io.*;
import java.util.*;
public class Solution {
public static void main(String[] args) {
// Enter your code here
Scanner scanner = new Scanner(System.in);
int num = scanner.nextInt();
System.out.println(num * 2);
}
}
C#:
using System;
using System.Collections.Generic;
using System.IO;
class Solution {
static void Main(String[] args) {
// Enter your code here
int num = Int32.Parse(Console.ReadLine());
Console.WriteLine(num * 2);
}
}
VB.NET:
Module Solution
Sub Main()
' Enter your code here
Dim num As Integer = Integer.Parse(Console.ReadLine())
Console.WriteLine(num * 2)
End Sub
End Module
JavaScript (Node.js)
process.stdin.resume();
process.stdin.setEncoding('ascii');
var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;
process.stdin.on('data', function (data) {
input_stdin += data;
});
process.stdin.on('end', function () {
input_stdin_array = input_stdin.split("\n");
main();
});
function readLine() {
return input_stdin_array[input_currentline++];
}
function main() {
// Enter your code here
var num = parseInt(readLine());
console.log(num * 2);
}
C++ 11:
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() {
// Enter your code here
string sNum;
getline(cin, sNum);
int num = stoi(sNum);
cout << num * 2 << "\n";
return 0;
}
Note: one advantage of using getline for c++ input is that when multiple values are provided on one line of input (e.g. 2 3 5 7) then you can easily read through to the next delimeter e.g.
getline(cin, sNum, ' ');
However, of course, you could also in this case just do the shorter:
#include <iostream>
using namespace std;
int main() {
// Enter your code here
int num;
cin >> num;
cout << num * 2 << "\n";
return 0;
}