C :

#include<stdio.h>
#include<string.h>
int main()
{
	char a[204],i,l;
	gets(a);
	l=strlen(a);
	for(i=0;i<l;i++)
	{
		if(a[i]=='a'||a[i]=='A')
			printf("%c",a[i]);
		if(a[i]=='o'||a[i]=='O')
			printf("%c",a[i]);
		if(a[i]=='e'||a[i]=='E')
			printf("%c",a[i]);
		if(a[i]=='i'||a[i]=='I')
			printf("%c",a[i]);
		if(a[i]=='u'||a[i]=='U')
			printf("%c",a[i]);
	}
	printf("\n");
	return 0;
}

C++ :

#include <stdio.h>
#include <string.h>
int main() {
	void pick(char str[], int l, char out[]);
	char str[101], out[101];
	gets(str);
	pick(str, strlen(str), out);
	puts(out);
	return 0;
}
char tolower(char a) {
	if ('A' <= a && a <= 'Z')
		return 'a' + (a - 'A');
	return a;
}
void pick(char str[], int l, char out[]) {
	int i, lout = 0;
	for (i = 0;i < l;i++)
		if (tolower(str[i]) == 'a' || tolower(str[i]) == 'e' || 
			tolower(str[i]) == 'i' || tolower(str[i]) == 'o' || 
			tolower(str[i]) == 'u') {
			out[lout++] = str[i];
		}
	out[lout] = '\0';
}

Pascal :

var
  s:string;
  
function get(s:string):string;
var i:longint; c:char;
begin
  for i:=1 to length(s) do begin
    c:=upcase(s[i]);
    if(c in ['A','I','O','U','E']) then
      get:=get+s[i];
  end;
end;

begin
  readln(s);
  writeln(get(s));
end.

Java :

import java.util.Scanner;

public class Main {
   private static Scanner s = new Scanner(System.in) ;
   
   public static void main(String[] args) {
	  String str = s.nextLine() ;
	  
	  char c[] = str.toCharArray() ;
	  
	  for (int i = 0; i < c.length; i++) {
		  if(c[i]=='a'||c[i]=='e'||c[i]=='i'||c[i]=='o'||c[i]=='u'||
				  c[i]=='A'||c[i]=='E'||c[i]=='I'||c[i]=='O'||c[i]=='U'){
			  System.out.print(c[i]);
		  }
	  }
	  System.out.println();
   }
}