It’s testing the ith bit. Returns true if the ith bit is 1
Eg suppose x is 00001000 and I is 3
The 1 is 00000001
1<<3 is 00001000
X is. 00001000
AND is 00001000. Which is != 0, so the result is. True
Now suppose I = 2
1<<2 is 00000100
X is. 00001000
AND is 00000000. Which is not...