V.size () return size_t not int returns the number of unsigned integers

In the C + + STL, the vector size () function return size_t, which is unsigned int, not int. So imagine this, define an empty vector<int> V, and v.size () should is 0, and you had a for loop, and had an end co Ndition is V.size ()-1, which is 4294967295 actually, not-1. This might cause problem when i = 0, which can enter the as loop, but actually is supposed not entering it.

vector<int>V;cout<< v.size () << Endl;//0cout << v.size ()-1<< Endl;//4294967295cout << v.size ()-2<< Endl;//4294967294cout<< v.size () << Endl;//0cout <<int(V.size ()-1) << Endl;//-1cout <<int(V.size ()-2) << Endl;//-2

V.size () return size_t not int returns the number of unsigned integers