Java += Means What?

Question

In Java what does += do or mean?

for example:

devtop += Math.pow(x[i] - mean, 2);

Answer 1

It will add the result of the operation Math.pow(x[i] - mean, 2) to the devtop variable.

A more simple example:

int devtop = 2;
devtop += 3; // devtop now equals 5

Answer 2

It's a compound assignment operator. It's equivalent to:

devtop = devtop + Math.pow(x[i] - mean, 2);

In general, x $= y where $ is an operator is identical to x = x $ y.

Answer 3

a += b is short hand for a = a + b

Answer 4

Add Math.pow(x[i] - mean, 2) to devtop.