Question

Specifically, could you tell me what this line of code does:

int var1 = (var2 + 7) & ~7;

Thanks

Answer 1

It’s bitwise negation. This means that it performs the binary NOT operator on every bit of a number. For example:

int x = 15; // Binary: 00000000 00000000 00000000 00001111
int y = ~x; // Binary: 11111111 11111111 11111111 11110000

When coupled with the & operator it is used for clearing bits. So, in your example it means that the last 3 bits of the result of var2+7 are set to zeroes.

As noted in the comments, it’s also used to denote destructors, but that’s not the case in your example.