Question

Can someone explain how typecasting works in the line int y = (int) x;
Thank You

public class typecast
{
 public static void main(String [] args)
 {
  double x=10.5;
  int y=(int) x;
  System.out.println("x="+x);
  System.out.println("y="+y);
 } 
}

Answer 1

The type cast performs a narrowing type conversion. The exact conversion depends on the double value, as follows:

• If it is within the range of int values, it is rounded towards zero.
• If it outside of the range or is an “Inf” value, then the conversion gives Integer.MIN_VALUE or Integer.MAX_VALUE, depending on the sign.
• If it is a “NaN” value, the conversion gives zero.

Reference: JLS 5.1.3

Note: “round towards zero” is defined as follows:

“The Java programming language uses round toward zero when converting a floating value to an integer (§5.1.3), which acts, in this case, as though the number were truncated, discarding the mantissa bits. Rounding toward zero chooses at its result the format’s value closest to and no greater in magnitude than the infinitely precise result.“