struct record { const char* id; int count; };

const char* foo()
{
    std::map< const char* , size_t > counters;
#if 1
    for( record r : std::initializer_list<record>{
            { "a", 1 },
            { "a", 2 },
            { "b", 3 },
            { "b", 4 },
            { "a", 5 },
            { "a", 6 },
            { "c", 7 },
            { "c", 8 },
            { "a", 9 },
        })
        counters[r.id]+=r.count ;
#else
    for( record r : {
            record{ "a", 1 },
            record{ "a", 2 },
            record{ "b", 3 },
            record{ "b", 4 },
            record{ "a", 5 },
            record{ "a", 6 },
            record{ "c", 7 },
            record{ "c", 8 },
            record{ "a", 9 },
        })
        counters[r.id]+=r.count ;
#endif
    return counters.begin()->first;
};

String literals have static storage duration, and thus exist in memory for the life of the program.

const char* foo()
{
  const char* p1 = "a";
  const char* p2 = "a";
  const char* p3 = p1;
  p3 = p2;
  return p3; 
}

const char* foo()
{
  const char** p3;
  {
    const char* p1 = "a";
    const char* p2 = "a";

    p3 = new const char*;
    *p3 = p1;
    *p3 = p2;
  } 
  
  const char* p4 = *p3;
  delete p3;
  return p4; 
}

#include <boost/range/adaptor/map.hpp>
#include <iostream>
#include <map>

std::map<int, const char*> makeMap()
{
    return {
        {1, "one"},
        {2, "two"},
        {3, "three"},
        {4, "four"},
        {5, "five"},
    };
}

int main()
{
    for (const char* value : makeMap() | boost::adaptors::map_values)
    {
        std::cout << " " << value;
    }
    std::cout << std::endl;
}