显式类型转换为字节溢出

Question

public class {
    public static void main(String[] args) {
        // Explicit Type Conversion
        long t = 70;
        t= (byte) t * 2;
        System.out.println("Manual conversion"+t);
    }
}

Output :- Manual Conversion 140

Here am getting the output 140, but why? Because as byte ranges from -128 to 127 so why am getting 140, as its more than 127, it's exceeding!

Answer 1

Let's examine the expression t=(byte)t*2 . You have a byte (since you explicitly cast it) multiplied by an int (literal). The left operand is promoted to an int in order to perform the multiplication, so 140 is a valid value there. It is then promoted to a long and assigned back to t .

Answer 2

Cast has higher operator precedence than multiplication. Use

t=(byte)(t*2)