how do i print out in c++ and linux terminal

Question

#include <iostream>
#include <vector>
#include <unordered_map>
using namespace std;
class twoSumClass{
    public:
        vector<int> twoSum(vector<int>& nums, int target){
           vector<int> result;
           unordered_map<int,int> hm;
           for(int index = 0; index < nums.size(); index++){
            int findVal = target - nums[index];
            if(hm.count(findVal) > 0 && hm[findVal] != index){
                result.push_back(index);
                result.push_back(hm[findVal]);
                return result;
            }
            else{
                hm.insert(make_pair(nums[index], index));
            }
           }
           return result;
        }
};
void Print(vector<int>& v){
    for (int i = 0; i < v.size(); i++){
        cout << v[i] <<endl;
    }
};
int main(){
    vector<int> items = {1,2,3,4,5,6,7};
    int trgt = 2;
    twoSumClass myTest;
    std::vector<int> res = myTest.twoSum(items, trgt);
    Print(res);
    return 0;
}

this is my simple code, I am trying run this code in linux terminal as: g++ test1.cpp -o test1, and then run: ./test1 however, terminal does not print anything. how do i change code? BTW, the purpose of code is similar with leetcode question #1 add two sum.

Answer 1

int main() {
    vector<int> items = {1,2,3,4,5,6,7};
    int trgt = 2;
    ...
}

You want to find out 2 integers in vector items and their sum equals trgt.
There is no answer in {1,2,3,4,5,6,7}.
So no print is the correct answer.

Advise you to read this guide.