how to delete first element in vector code example

Example 1: remove element by value vector c++

#include<bits/stdc++.h>
using namespace std;
int main(){
    vector<int> v;
    //Insert values 1 to 10
    v.push_back(20);
    v.push_back(10);
    v.push_back(30);
    v.push_back(20);
    v.push_back(40);
    v.push_back(20);
    v.push_back(10);

    vector<int>::iterator new_end;
    new_end = remove(v.begin(), v.end(), 20);

    for(int i=0;i<v.size(); i++){
        cout << v[i] << " ";
    }
    //Prints [10 30 40 10]
    return 0;
}
C++Copy

Example 2: vector erase specific element

template <typename T>
void remove(std::vector<T>& vec, size_t pos)
{
    std::vector<T>::iterator it = vec.begin();
    std::advance(it, pos);
    vec.erase(it);
}