Added cpp solution for Concatenation-of-Array

[Divyamsirswal]

#include<bits/stdc++.h>
using namespace std;

vector<long long> concatArray(vector<long long>& arr){
  vector<long long> temp;
  for(int i=0;i<arr.size();i++){
    temp.push_back(arr[i]);
  }
  for(int i=0;i<arr.size();i++){
    temp.push_back(arr[i]);
  }
  return temp;
}

int main(){
  long long num;
  cin>>num;

  vector<long long> arr(num);

  for(int i=0;i<num;i++){
    cin>>arr[i];
  }

  vector<long long> temp = concatArray(arr);

  for(int i=0;i<temp.size();i++){
    cout<<temp[i]<<" ";
  }

}