c++ - fast way to get integers 0, 1, and 2 when given a random one from the set -

so basically

int num = rand(2); //random number 0-2 int othernum, otherothernum; othernum = implement otherothernum = implement 

for example, if num 2, othernum , otherothernum must set 0 , 1 (or 1 , 0).

how implement this? assume can't use branching or tables. yes i'd bit manipulation solution. yes i'd solution faster solution uses modulus operator (as essentialy division).

i think lookup might fastest not sure, dont solution though.

you can xor , bit masking.

#include <stdio.h>  void f(unsigned val, unsigned ary[3]) {     ary[0] = val;     ary[1] = (ary[0] ^ 1) & 1;     ary[2] = (ary[0] ^ 2) & 2; }  int main() {     unsigned ary[3] = {0};      f(0, ary);     printf("f(0) = %d %d %d\n", ary[0], ary[1], ary[2]);      f(1, ary);     printf("f(1) = %d %d %d\n", ary[0], ary[1], ary[2]);      f(2, ary);     printf("f(2) = %d %d %d\n", ary[0], ary[1], ary[2]);      return 0; } 

this print:

f(0) = 0 1 2 f(1) = 1 0 2 f(2) = 2 1 0