Hi. I'm reading The C Programming Language and I am having a hard time understanding this. On page 48, when the authors present the bitwise operators, they have this as an example for the & operator:

n = n & 0177;

"sets to zero all but the low-order bits of n."

I know 0177 is an octal number but that's all I understand. Could someone explain this to me in details and then suggest me a good reading on number bases, binary numbers and bitwise operations?