I have 5 objects, a
, b
, c
. d
and e
. The 5 objects hashcodes are as follows:
a => 72444
b => 110327396
c => 107151
d => 2017793190
e => 68574749
As you can see, all are positive values. However, when I sum them up into a long
-variable, the result comes out negative:
long sum = a+b+c+d+e;
System.out.println(sum); // prints -2098092366
The sum of these ints far below the max-value of long
(9223372036854775807), yet it yields a negative result. Why?
That happens because your variables are all int
s, so you to int
addition (which overflows), and then the final result is converted to long
.
You can fix this by casting the first variable to long
:
long sum = (long)a + b + c + d + e;
Integer values can be -2,147,483,648 to 2,147,483,647. The sum actually exceeds the max value and trancted for numeric overflow
.
int x = 2147483647;
x++;
System.out.println(x);
It prints - -2147483648
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