Dijkstra shortest path algorithm implementation code

Dijkstra's shortest path algorithm is calculated based on the shortest path of the precursor vertex. Generally speaking, it is relatively simple. The following is the code:

#include <iostream>
#include <vector>
#include <limits>
void shortestpath( const std::vector <std::vector< short> >& paths, int from, std::vector< short>& path){
    std:: vector<bool> flags(paths.size(), false);
    std:: vector<short> distance(paths.size(), 0);
    path.resize(paths.size(), 0);
    for(size_t i = 0; i != paths.size(); ++i){
        distance[i] = paths[from][i];
    }
    flags[from] = 1;
    int min, pos;
    for(size_t i = 1; i != paths.size(); ++i){
        pos = -1;
        min = std:: numeric_limits<short>::max();
        for(size_t j = 0; j != paths.size(); ++j){
            if(!flags[j] && distance[j] < min){
                min = distance[j];
                pos = j;
            }
        }
        if(pos == -1)
            break;
        flags[pos] = true;
        for(size_t j = 0; j != paths.size(); ++j){
            if(!flags[j] && paths[pos][j] != 0
                && paths[pos][j] < std::numeric_limits <int>:: max()
                && min+paths[pos][j] < distance[j]){
                distance[j] = min + paths[pos][j];
                path[j] = pos;
            }
        }
    }
    for(size_t i = 0; i != distance.size(); ++i){
        std::cout << distance[i] << " " << std::flush;
    }
    std::cout << std:: endl;
}
int main(){
    std::cout << " Please enter the number of vertices: " << std::flush;
    int sum; std::cin >> sum;
    std:: vector<std::vector <short> > paths;
    for(int i = 0; i != sum; ++i){
        paths.push_back(std:: vector<short>(sum, std::numeric_limits< short>::max()));
        paths[i][i] = 0;
    }
    std::cout << " Please enter the number of edges: " << std::flush;
    std::cin >> sum;
    int vi, vj, weight;
    for(int i = 0; i != sum; ++i){
        std::cin >> vi >> vj >> weight;
        paths[vi][vj] = weight;
        paths[vj][vi] = weight;
    }
    std:: vector<short> path;
    shortestpath(paths, 0, path);
    std::cout << " The result of the nearest path is: " << std::flush;
    for(size_t i = 0; i != path.size(); ++i){
        std::cout << path[i] << " " << std::flush;
    }
    std::cout << std:: endl;
    return 0;
}