EXPLAIN THE USAGE OF CONVERSION JAVA PROGRAM

import java.util.*;
class type conversion
{
public static void main (string args[])
{
int a,b;
float r;
scanner os= new scanner (system.in);
system.out.println("enter any 2 integer :");
a=os.next int
b= os.next int
r=(float) a/b;
system.out.println("ratio of a,b :" +r);
}
}