execute{

function swap(p1, p2) { //this function basicly changes the values of p1 and p2.

temp=p1; p1=p2; p2=temp;

}

p1=10; p2=20;

swap(p1, p2);

writeln("p1=", p1 ); writeln(''p2='' , p2); }

the out put must be p1=20 ; p2=10

but it is not. how can i make this function work???