This example shows how a multiplication of 2 integer (unsigned) number may be done over shifting and addition
It does not consider the sign and works for int type, but when needed can be expanded to the datatypes of wider range
It also does not consider an overflow after shifting, but pay attention at the interesting fact: if multiplication results into a number
that is bigger than uint can hold, then result will be wrong, but it will be the same as default multiplication implementation gives.
Try multiplying 99999 and 99999. Whereas the correct result is 9999800001, the program will produce 1409865409 for both
custom multiplication and default * opertion.
By controlling the overflow and managing arrays of numbers it is theoretically possible to operate on numbers of any range.