我在用vector练习，我想push_back();用for循环来push一个元素，但是程序连for循环都进不去，求救！！！
#include <iostream>
#include <vector>
using namespace std;
int main()
{
cout << "check ";
int val;
vector<char> vec;
cout << "check " << endl << "Its in the game";
//those two "check" were to confirm if the program is even running and is it a
problem while declaring the vector
for(int i = 0; i < vec.size(); i++){
cout << "enter element for vector" << endl;
cin >> val;
vec.push_back(val);
}
}