What does the incremental operator '++' do in C?

The incremental operator '++' in C serves to increase the value of a variable by one. It is a unary operator that can be placed before or after the variable. When used before the variable (prefix form), it increments the value first and then returns the updated value. When used after the variable (postfix form), it returns the original value and then increments it.

This operator is an efficient way to increase numeric values in loops or when performing iterative calculations, making it a widely used feature in programming languages like C. In contrast, other choices presented do not accurately describe the function of the increment operator, as none involve changing the variable by a value other than one, nor do they involve resetting the variable or decreasing its value.