The unary minus operator looks like the binary minus operator, it is in fact the same character. The difference is purely syntactical. There is only one operand of the unary minus (or implicitly one is subtracting from zero). This operand can be either of an integer or floating type.
Unary minus can occur at the beginning of an expression, or after a left parenthesis, or after another operator. Here is an example with all three:
z=-y*(-t*-w);
There is also a unary plus for consistency but semantically it has no effect. There is no calculation made if it is used.