[Solved] Need a simple help in C [closed]

Part 1

Firstrly result &= 0 is used for setting 0 to result variable using bitwise AND operation. Bitwise with 0 will ever return 0.

You can write it simply this way: result = 0

The better (much optimal) way of doing this is: result ^= result. (Bitwise XOR)

Part 2

This loop will iterate while m is greater (or less) than 0. Because m expression will return true if m != 0.

Much secure way of doing it is m > 0.

Also you can use this expression, which is not making programm much optimal, but it will be cleaner to another programmer to understand your code: !!m (casting m variable to bool), which is equal to m != 0;

Part 3

In this part ternary operator (logical_expression ? expression_1 : expression_2) is used.
If logical_expression is true, then expression_1 will be executed, expression_2 will be executed otherwise.

So in your code, if this expression (arr[--m] & (0x1 << 0x1F)) returns true then we add arr[m] to result variable. And do nothing in another case.

Also m variable is decremented in ternary logical expression (arr[--m]).