swapping two number a and b: a=a^b b=b^a a=a^b

Exctract ith bit from binary nuber

int getithbit(int n, int i) int mask=(1<<i); return n & mask!=0?1:0;

set the ith bit

int getithbit(int n, int i) return n | (1<<i)!=0?1:0;

clear the ith bit to 0 clearBit(int n, int i){ int mask= ~(i<<i); n= n & mask;