Python 2

N = int(raw_input())

for _ in xrange(N):
    a, b = map(int, raw_input().split())
    print a + b

Python 3

N = int(input())

for _ in range(N):
    a, b = map(int, input().split())
    print(a + b)

Java

import java.util.*;

public class APlusB {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        int N = in.nextInt();
        for (int i = 0; i < N; i++) {
            int a = in.nextInt();
            int b = in.nextInt();
            System.out.println(a + b);
        }
    }
}

C++

#include <iostream>

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 << endl;
    }
}

C

#include <stdio.h>

int main() {
    int N;
    scanf("%d\n", &N);

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

JS

print(...): similar to Python's print, prints all argument separated by space followed by new line.
flush(): flushes stdout, ensuring everything output by print() immediately shows up.
gets(): similar to the Ruby equivalent, returns one line of input from stdin.
read(bytes): read bytes bytes from stdin as an ArrayBuffer.
write(buffer): write a typed array, ArrayBuffer, or a view of ArrayBuffer to stdout.
quit(code): exits the program with code.
You can also assign to the global variable autoflush to control whether print() flushes.