Data type casting

CODE

class DatatypeCasting
{
    public static void main(String arg[])
    {
        byte b;
        int i = 81;
        double d = 323.142;
        float f = 72.38f;
        char c = 'A';
        
        c = (char) i;
        System.out.println("i = " + i + " c = " + c);
        
        i = (int) d; // LINE A
        System.out.println("d = " + d + " i = " + i); // LINE B
        
        i = (int) f; // LINE C
        System.out.println("f = " + f + " i = " + i); // LINE D
        
        b = (byte) d;
        System.out.println("d = " + d + " b = " + b);
    
    }
}

OUTPUT

i = 81 c = Q
d = 323.142 i = 323
f = 72.38 i = 72
d = 323.142 b = 67

DESCRIPTION

When i is casted to c the value corresponding to the ascii code of 81 which is 'Q' is assigned.
When d is casted to i the decimal part .142 is truncated and only 323 is assigned to i.
Similarly when f is casted to i, the decimal part .38 is truncated and only 72 is assigned to i.
When d is casted to b whose range is -128 to 127, not only the decimal part .142 is truncated but it is also shortened from 323 to 67 so as to fit in byte range.

THINGS TO TRY

Change initialization value of d from 323.142 to 2.75E+19 which is much higher than integer range and see what value will be printed in LINE B.

Change initialization of f from 72.38f to 72 and see what gets printed in LINE D.

Remove the type cast from d to i in LINE A, i.e. change i = (int) d; to i = d; and see that you get 'possible loss of precision' compilation error.

Try it Online

Data type casting - Java Example Program