build.ninja

rule kompile
  command = g++ -std=c++20 -c $in -o $out

rule linkkaa
  command = g++ $in -o $out && rm -f umap.o

build umap.o: kompile umap.cpp
build umap.exe: linkkaa umap.o
default umap.exe

umap.cpp

#include<iostream>
#include<unordered_map>
#include<string>

using namespace std;

int main()
{
        unordered_map um;
        um["95400"] = "Tornio";
        um["50100"] = "Mikkeli";
        um["51200"] = "Kangasniemi";
        um["85470"] = "Sievi";
        um["92700"] = "Kestilä";

// Traversing an unordered map
        for (auto x : um)
         cout << x.first << " " << x.second << endl;

        cout << "Loppu\n";
        return 0;
}