Using a common expression with IOTA. Sometimes it is necessary to define a list of constants with values that are computed according to certain rules. In this case, after the const keyword, you need to specify one common expression that will be calculated for each constant in this definition. In this expression, you can use the special variable IOTA, which is equal to the ordinal index of the constant in the list, starting at zero. Constants should be separated by a space or a new line.