<![CDATA[import java.io.*;
public class expr
{
public String node;
public int level;
public expr prem[];
public int nprem;
expr (String nod, int np, expr p0, expr p1, expr p2)
{
node = nod;
level = 0;
nprem = np;
prem = new expr[3];
prem[0] = p0;
prem[1] = p1;
prem[2] = p2;
}
expr (String nod, int l, int np, expr p0, expr p1, expr p2)
{
node = nod;
level = l;
nprem = np;
prem = new expr[3];
prem[0] = p0;
prem[1] = p1;
prem[2] = p2;
}
void print (PrintStream out)
{
if (this == null)
out.print ("null");
else
{
out.print (node);
if (level != 0)
out.print (level);
if (nprem > 0)
{
out.print ("(");
prem[0].print (out);
for (int i=1; i<nprem; i++)
{
out.print (",");
prem[i].print (out);
}
out.print (")");
}
}
}
}
]]>