How to fix an error with adding integers in Java?

Question

In given example:

int a, b, c;
a = 2111000333;
b = 1000222333;
c = a + b;
System.out.println("c= " + c);

will return: c= -1183744630 , why?

How to fix that?

Answer 1

Your integer is overflowing. An integer has a maximum value of Integer.MAX_VALUE (2^31 - 1). If the value becomes bigger, your variable will not have the right value anymore.

A long has a bigger range.

long a, b, c;
a = 2111000333;
b = 1000222333;
c = a + b;
System.out.println("c= " + c);

Answer 2

The MAX_VALUE of a Java long is 9223372036854775807, so Scharrels' solution works for your example.

Here's another solution that can go even higher, should you need it.

BigInteger a = new BigInteger(2111000333);
BigInteger b = new BigInteger(1000222333);
BigIntegerc = a.add(b);
System.out.println("c= " + c);

This approach is bounded only by JVM memory.