PL/SQL Procedure Program for Swapping of two Number

In this PL/SQL program, you will perform swapping two numbers using a procedure of PL/SQL

declare
x number;
y number;
temp number;
 procedure MySwap(a in out number,b in out number)
 is
 begin
 dbms_output.put_line('before swapping a='||a||' b='|| b);
 temp:=a;
 a:=b;
 b:=temp;
 dbms_output.put_line('After swapping a='||a||' b='|| b);
end;
begin
x:=&x;
y:=&y;
MySwap(x,y);
end;
/

output

Enter value for x: 10
old  15: x:=&x;
new  15: x:=10;
Enter value for y: 12
old  16: y:=&y;
new  16: y:=12;
before swapping a=10 b=12
After swapping a=12 b=10