size_t vs int warning

Question

I am getting following warning always for following type of code.

std::vector v;
for ( int i = 0; i < v.size(); i++) {
}

warning C

Answer 1

is this safe to ignore this warning or should I make all my loop variable of type size_t

No. You are opening yourself up to a class of integer overflow attacks. If the vector size is greater than MAX_INT (and an attacker has a way of making that happen), your loop will run forever, causing a denial of service possibility.

Technically, std::vector::size returns std::vector::size_type, though.

You should use the right signedness for your loop counter variables. (Really, for most uses, you want unsigned integers rather than signed integers for loops anyway)