C++ :

#include<iostream>
#include<cstdio>
using namespace std;
char s1[201],s2[101];
void copyvowels(char a[],char b[])
{
	for (int i=0,j=0; a[i]!='\0'; 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')
			b[j++]=a[i];
}
int main()
{
	gets(s1);
	copyvowels(s1,s2);
	cout<<s2<<endl;
	return 0;
}

Pascal :

var st:string;
    i:longint;
begin
  readln(st);
  for i:=1 to length(st) do
  if (st[i]='a') or (st[i]='e') or (st[i]='i') or (st[i]='u') or (st[i]='o') then
  write(st[i]);
end.