push front of vector c++
#include <iostream>
#include <vector>
using namespace std;
int main() {
vector<int> vec;
vec.insert(vec.begin(), 10);
vec.insert(vec.begin(), 20);
vec.insert(vec.begin(), 30);
for (int i = 0; i < vec.size(); i++) {
cout << vec[i] << " ";
}
return 0;
}