[email protected] wrote: > ankur_sh2001 wrote: >> how to add 4 long integers >> like >> 562715478678943549...........100 times >> 562715478678943549...........100 times >> 562715478678943549...........100 times >> 562715478678943549...........100 times > > That will exceed the size of an unsigned 64-bit integer. For working > with really large numbers, you will need an arbitrary precision math > library. > > BTW, 562715478678943549 * 100 = 56271547867894354900...multiplying by > 10^n is easy - tack the number of zeros corresponding to 'n' onto the > end of the other number. In this case, two zeros. >
Tacking on two zeros to simulate multiplying by 100 works if you care about displaying the result but it does not work in terms of storing the result unless your number storage is done in base 10. For computers that store things in collections of binary bits the following are easy: - Simulate multiplying by 2 by adding 1 zero bit (left shift by 1) - Simulate multiplying by 4 by adding 2 zero bit (left shift by 2) - Simulate multiplying by 8 by adding 3 zero bit (left shift by 3) - Simulate multiplying by 16 by adding 4 zero bit (left shift by 4) - and so on.
