How to append a vector in a vector in C++?

To append a vector in a vector can simply be done by vector insert() method.

Algorithm

Begin
   Declare a function show().
      Pass a constructor of a vector as a parameter within show()
      function.
      for (auto const& i: input)
         Print the value of variable i.
   Declare vect1 of vector type.
      Initialize values in the vect1.
   Declare vect2 of vector type.
      Initialize values in the vect2.
   Call vect2.insert(vect2.begin(), vect1.begin(), vect1.end()) to
   append the vect1 into vect2.
   Print “Resultant vector is:”
   Call show() function to display the value of vect2.
End.

Example Code

Live Demo

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
void show(vector<int> const &input) {
   for (auto const& i: input) {
      std::cout << i << " ";
   }
}
int main() {
   vector<int> v1 = { 1, 2, 3 };
   vector<int> v2 = { 4, 5 };
   v2.insert(v2.begin(), v1.begin(), v1.end());
   cout<<"Resultant vector is:"<<endl;
   show(v2);
   return 0;
}