Analysing &, && and | for this code?

Question

I want to illustrate the difference with this code

for(i = 32; i > 0; i--)
 {
   if(a&1 != 0) //bit mask
     total += b;
   a = a >> 1;
   b = b << 1; 
 }

In the code & is used to "mask" a bit and the result would have been completely different if && had been used instead. In that case the expression 1 had been interpreted as a truth value (TRUE) instead of a one-bit position that is used to keep one of the bits. Correct? But what would instead happen if I did like this:

for(i = 32; i > 0; i--)
 {
   if(a|1 != 0) //bit mask
     total += b;
   a = a >> 1;
   b = b << 1; 
 }

In the first case the 1 is used to keep only the LSB (least significant bit) i.e. rightmost bit and nothing else. What would |do in its place? What would be the difference if I did this change?

Answer 1

a&1 != 0

should be

(a&1) != 0

!= has higher precedence than &. Otherwise a&1 != 0 is read as a & (1 != 0).

Same for (a|1 != 0).