C :

#include<stdio.h>
int main()
{
	int a1,a2,i,a3;
	a1=0;a2=1;
	printf("%d %d",a1,a2);
	for(i=3;i<=21;i++)
	{
		a3=a1+a2;
		printf(" %d",a3);
		a1=a2;
		a2=a3;
	}
	return 0;
}

C++ :

#include<iostream>
using namespace std;
int main()
{
  int a=0,b=1,c;
  cout<<a<<" "<<b;
  for (int i=1;i<=19;++i)
    {
      c=a+b;
		cout<<" "<<c;
		a=b;b=c;
     }
	return 0;
}

Pascal :

program ex_1;
begin
 writeln('0 ','1 ','1 ','2 ','3 ','5 ','8 ','13 ','21 ','34 ','55 ','89 ','144 ','233 ','377 ','610 ','987 ','1597 ','2584 ','4181 ','6765');

end.