C :

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

int main()
{
	int t,i;
	char a[51];
	scanf("%d%*c",&t);
	while(t--)
	{
		gets(a);
		for(i=0;i<strlen(a);i++)
		{
			if(a[i]=='A'||a[i]=='a'||a[i]=='E'||a[i]=='e'||a[i]=='I'||a[i]=='i'||a[i]=='O'||a[i]=='o'||a[i]=='U'||a[i]=='u')
				a[i]=toupper(a[i]);
			else
				a[i]=tolower(a[i]);
		}
		puts(a);
	}
	return 0;
}

C++ :

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

int main()
{
	int t,i;
	char a[51];
	scanf("%d%*c",&t);
	while(t--)
	{
		gets(a);
		for(i=0;i<strlen(a);i++)
		{
			if(a[i]=='A'||a[i]=='a'||a[i]=='E'||a[i]=='e'||a[i]=='I'||a[i]=='i'||a[i]=='O'||a[i]=='o'||a[i]=='U'||a[i]=='u')
				a[i]=toupper(a[i]);
			else
				a[i]=tolower(a[i]);
		}
		puts(a);
	}
	return 0;
}

Pascal :

var n,i,j:integer;
    a:string;
begin
  readln(n);
  for i:=1 to n do begin
    readln(a);
    for j:=1 to length(a) do 
      if ord(a[j])<=90 then a[j]:=chr(ord(a[j])+32);
    for j:=1 to length(a) do begin
      if (a[j]='a') or (a[j]='e') or (a[j]='i') or (a[j]='o') or (a[j]='u') then write(upcase(a[j])) else write(a[j]);
    end;
    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){
			String s = in.next();
			StringBuffer sb = new StringBuffer();
			for(int i=0;i<s.length();i++){
				char c = s.charAt(i);
				if(c>'Z'){
					if(c=='a'||c=='e'||c=='i'||c=='o'||c=='u')sb.append((char)(c-'a'+'A'));
					else sb.append(c);
				}else {
					if(c=='A'||c=='E'||c=='I'||c=='O'||c=='U')sb.append(c);
					else sb.append((char)(c-'A'+'a'));
				}
			}
			System.out.println(sb);
		}
	}
}

Python :

import sys

l = 1
Z = ['a','e','i','o','u','A','E','I','O','U']
for line in sys.stdin:
    data = list(line.split()[0])
    if l!=1:
       r = map(lambda x:x.upper() if x in Z else x.lower(),data)
       print ''.join([i for i in r])
    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 ans = string.Empty;
                str=str.ToLower();
                for (int i = 0; i < str.Length; i++)
                {
                    if (str[i].Equals('a') || str[i].Equals('i') || str[i].Equals('e')
                        || str[i].Equals('u') || str[i].Equals('o'))
                    {
                        ans += str[i].ToString().ToUpper();
                    }
                    else ans += str[i].ToString();
                }
                    Console.WriteLine(ans);
                t--;
            }
        }
    }
}