core - Arithmatic Operation in Java -

assume have 1 arithmetic function add 2 long variables , return long value. if pass long.maxvalue() argument wont give perfect result. solution that? code below explains mean:

public class arithmaticexample {         public static void main(string[] args) {         system.out.println(arithmaticexample.addlong(long.max_value, long.max_value));     }      public static long addlong(long a,long b){         return a+b;     }        }  

so can see wood trees, let's recast problem using byte rather long , consider

byte = 0b01111111; // i.e. 127, largest value of `byte`. byte b = 0b01111111; byte c = (byte)(a + b); 

where need explicit cast circumvent conversion of a + b int.

computing c hand gives 0b11111110. is, of course, bitwise representation of -2 in 8 bit 2's complement type.

so answer byte case -2. , same holds true long: there more 1 bits contend in addition.

note although well-defined in java, same cannot said c , c++.

if need add 2 long values of such magnitude consider using biginteger.