C :

#include<stdio.h>
#include<string.h>

int main()
{
	int n,i,j;
	char a[50],b[50],c[100];
	scanf("%d",&n);
	while(n--)
	{
		scanf("%s%s",a,b);
		for(i=0;i<strlen(a)/2;i++)
			c[i]=a[i];
		for(i=strlen(a)/2,j=0;j<strlen(b);i++,j++)
			c[i]=b[j];
		for(j=strlen(a)/2;a[j]!='\0';i++,j++)
			c[i]=a[j];
		c[i]='\0';
		printf("%s\n",c);
	}
	return 0;
}

C++ :

#include<stdio.h>
#include<string.h>

int main()
{
	int n,i,j;
	char a[50],b[50],c[100];
	scanf("%d",&n);
	while(n--)
	{
		scanf("%s%s",a,b);
		for(i=0;i<strlen(a)/2;i++)
			c[i]=a[i];
		for(i=strlen(a)/2,j=0;j<strlen(b);i++,j++)
			c[i]=b[j];
		for(j=strlen(a)/2;a[j]!='\0';i++,j++)
			c[i]=a[j];
		c[i]='\0';
		printf("%s\n",c);
	}
	return 0;
}

Pascal :

var t,k,i:longint;a,b:string;
begin
 readln(t);
 for k:=1 to t do begin
  readln(a);
  readln(b);
  for i:=1 to length(a) div 2 do write(a[i]);
  write(b);
  for i:=length(a) div 2+1 to length(a) do write(a[i]);
  writeln;
 end;
end. 

Java :

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int t = in.nextInt();
		while(t-->0){
			StringBuffer sb = new StringBuffer(in.next());
			sb.insert(sb.length()/2, in.next());
			System.out.println(sb);
		}
	}

}

Python :

import sys
l,k,t,r= 1,0,[],[]
for line in sys.stdin:
    data = line.split()[0]
    if l !=1:
       k += 1
       if k%2 !=0:
          t = t+list(data)
       else:
          for j in range(len(t)/2):
              r.append(t[j])
          r.append(data)
          for j in range(len(t)/2):
              r.append(t[j+len(t)/2])
          print ''.join([i for i in r])
          k,t,r=0,[],[]
    l += 1
          
      
       

C# :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string str;
            int t=Convert.ToInt32(Console.ReadLine());
            while (t>0) 
            {
                str = Console.ReadLine();
                string str2 = Console.ReadLine();
                str = str.Insert(str.Length/2,str2);
                Console.WriteLine(str);
                t--;
            }
        }
    }
}