Discuss operator precedence in C programming with examples

See picture for the operator precedence.

A very common pitfall is the << (shift) operator.

It has lower precedence than, for instance, the + operator, so a statement like:

int a = 3;

int c = a << 2 + 1;

will produce a different result than:

int c = (a << 2) + 1;

The first will evaluate to c = a<<3.

which functions return a valid value without any arguments?

(-blank- and -blank- return a valid value without any arguments.)

1st -blank-

today

sqrt

count

2nd -blank-

round

now

sqrt