c++ STL vector如何删除

#include <iostream>using namespace std;#include <vector>int main(){  std::vector<int> a = {1, 2, 3, 4};  for(auto i = a.begin(); i != a.end(); )    if(*i == 3)      i = a.erase(i);    else      i++;  for(auto &i: a)    cout << i << " ";}