The minus sign as unary operator

To expand your thinking a little beyond Alice:

In Java, C++, and C#, as a unary operator, the minus sign causes the algebraic sign of the right operand to be changed.

For example, the following two statements cause a value of -5 to be stored in the variable x.

int y = 5;
int x = -y;

The above code is equivalent to the following:

int y = 5;
int x = 0-y;