Question:
There is a code
int a = Integer.MAX_VALUE;
int b = 5000;
int c = 123;
int min = Math.min(a, Math.min(b,c));
int max = Math.max(a, Math.max(b,c));
int d = a + b + c - min - max;
Why is the correct value stored in d ( b )?
After all, when we do a + b ( Integer.MAX_VALUE + 5000 ) we will have int'a overflow
Answer:
No, everything is correct. Together with overflows and it turns out.
Let's calculate step by step:
int step1 = a+b+c;
System.out.println(step1);
int step2 = step1-min;
System.out.println(step2);
int d = step2 - max;
System.out.println(d);
Output:
-2147478526
-2147478649
5000
It's just that at the last step, the second overflow -2147478649 -2147483647 and 5000 is obtained.
PS In general, the presence of overflow does not affect the associativity of the addition operation. In Java, addition of values of the same integer type is always associative, as mentioned in the specification ( §JLS 15.18.2 ):
Integer addition is associative when the operands are all of the same type.
Accordingly, for any a and b , the value of a + b - b will be equal to a .
It follows from this that in your case d will always be equal to the average of the three numbers ( a , b and c ) regardless of their values.