How do I read from STDIN and write to STDOUT in various languages

This is best explained with a simple problem statement and solutions in different languages.

Problem Statement

3
1 5
3 10
999 -34343

6
13
-33344
        

6
#include 
int main () {
    int n, i, a, b;

    scanf("%d", &n);
    for (i = 0; i < n; ++i) {
        scanf("%d %d", &a, &b);
        printf("%d\n", a+b);
    }
}
       

Solution

C++

6
#include 
using namespace std;

int main()
{
    int n;
    cin >> n;
    for(int i = 0; i < n; i++) {
        int a, b;
        cin >> a >> b;
        cout << a+b << "\n";
    }

    return 0;
}

Solution

C#

using System;
using System.IO;

class Solution {
    static void Main(String[] args) {
        int n = Convert.ToInt32(Console.ReadLine());
        for(int t = 0; t < n; t++) {
            String str = Console.ReadLine();
            String[] strArr = str.Split();
            int a = Convert.ToInt32(strArr[0]);
            int b = Convert.ToInt32(strArr[1]);
            Console.WriteLine(a+b);
        }
    }
}

Solution

Java

import java.io.*;
import java.util.*;

class Solution
{
    public static void main(String [] args) throws Exception
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        for(int t = 0; t < n; t++) {
            int a = sc.nextInt();
            int b = sc.nextInt();
            System.out.println(a+b);
        }
    }
}

Solution

Objective C

#import<Foundation/Foundation.h>

int main(int argc, const char* argv[])
{
    @autoreleasepool {
        NSInteger t;
        scanf("%lu", &t);

        for (NSInteger i = 0; i < t; i++) {
            NSInteger a, b;
            scanf("%lu %lu", &a, &b);

            /*
             * Do not use NSLog to print to stdout
             */
            printf("%lu\n", a + b);
        }

        return 0;
    }
}

Solution

Python

n = int(raw_input())
for i in range(0,n):
    a, b = raw_input().split()
    print int(a) + int(b)
    

Solution

Python 3

n = int(input())
for i in range(n):
    a, b = input().strip().split(' ')
    print (int(a) + int(b))

Solution

Ruby

n = gets.to_i
(0...n).each do |i|
    lis = gets.strip.split(" ")
    a = lis[0].to_i
    b = lis[1].to_i
    puts a + b
end

Solution

PHP

<!?php 
$handle = fopen ("php://stdin","r");
$t = fgets($handle);
for($i=0; $i<$t; $i++)
{
    $lis = explode(" ", fgets($handle));
    print((int)$lis[0] + (int)$lis[1]) . "\n";
}
fclose($handle);
?>

Solution

Javascript

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");
    var res;
    var n = parseInt(__input_stdin_array[__input_currentline].trim(), 10);
    __input_currentline += 1;
    for (var i = 0; i<n;i++) {
        var _line = __input_stdin_array[__input_currentline].trim();
        __input_currentline += 1;
        var line = _line.split(" ");
        var _a = parseInt(line[0]);
        var _b = parseInt(line[1]);
        res = _a + _b;
        process.stdout.write(""+res+"\n");
    }
});

Solution

Clojure

(use '[clojure.string :only (split triml)])
(def n (Integer/parseInt (read-line)))

(loop [i 0]
  (when (< i n)
    (def a (read-line))
    (def new (split a #"\s+"))
    (println ( + (Integer/parseInt (get new 0)) (Integer/parseInt (get new 1)) ))
    (recur (inc i))
))

Solution

Perl

$n = <>;
for($i=0; $i<$n; $i++)
{
    $lis = <>;
    @ll = split(' ', $lis);
    print $ll[0] + $ll[1];
    print "\n";
}

Solution

Haskell

import Control.Monad

main :: IO ()
main = do
  n <- readLn :: IO Int
  str <- replicateM n getLine
  let
    ans = map (sum. map read. words) str
  mapM_ print ans

Solution

Erlang

-module(solution).

-export([main/0]).

main() ->
    {ok, [N]} = io:fread("", "~d"),
    test(N).

test(0) -> ok;
test(N) ->
    {ok, [A, B]} = io:fread("", "~d ~d"),
    io:fwrite("~w~n", [(A + B)]),
    test(N-1).

Solution

Go lang

package main
import "fmt"

func main() {
  var n int
  var a int
  var b int
  fmt.Scan(&n)

  for i := 0; i < n; i++ {
    var sum int
    fmt.Scan(&a,&b)
    sum = a+b
    fmt.Println(uint(sum))
  }
}

Solution

Groovy

BufferedReader br = new BufferedReader(new InputStreamReader(System.in))
def a,b, res,line
def n = Integer.parseInt(br.readLine())
for (int i = 0; i < n; i++) {
    line = br.readLine()
    def (_a,_b) = line.split(' ')
    a = Integer.parseInt(_a)
    b = Integer.parseInt(_b)
    res = a+b
    println res
}

Solution

Scala

object Solution extends App {
  val n = readInt
  //recommended
  (1 to n).map(i => readLine.split(" ").map(_.toInt).sum).foreach(println)

  /*
    another way
    for (i <- 1 to n) {
    val Array(a, b) = readLine.split(" ").map(_.toInt)
    println(a + b)
  }
  */
}

Solution

R

f <- file("stdin")
open(f)

count = as.numeric(readLines(f, n = 1))

for(i in 1:count) {
    lines <- readLines(f, n = 1)
    num <- strsplit(lines, " ")[[1]]
    sum <- as.numeric(num[1]) + as.numeric(num[2])
    write(sum, stdout())
}

Solution

Swift

import Foundation

let t = Int(readLine()!)!

for i in 1...t {
    let nums = readLine()!.characters.split(" ").map{Int(String($0))!}
    let a = nums[0]
    let b = nums[1]

    print(a + b)
}