how to index a numeric value to return a string

Question

I have this enum

enum CombatType_t
{
    COMBAT_ICEDAMAGE    = 1 << 9, // 512
    COMBAT_HOLYDAMAGE   = 1 << 10, // 1024
    COMBAT_DEATHDAMAGE  = 1 << 11, // 2048
};

Basically, im trying to make a new array/list to be able to index an string by using a specific number to index CombatType_t

Something as the following:

enum AbsorbType_t
{
    "elementIce" = 512,
    "elementHoly" = 1024,
    "elementDeath" = 2048
}

In Lua, for example I could make an associative table

local t = {
    [512] = "elementIce"; 
}

And then, to index i could simply do t[512] which returns "elementIce"

How can I do this in C++?

Additionally, if you do not need the keys held in sort-order, then use std::unordered_map. For 3 entries -- it doesn't matter from a performance standpoint, but for 3-million it would. — David C. Rankin
– David C. Rankin, Commented Feb 6, 2022 at 9:30

nielsen · Accepted Answer · 2022-02-06 09:12:02Z

5

In C++, the standard way to make an associative table is std::map:

#include<iostream>
#include<map>
#include<string>
...

   std::map<unsigned, std::string> absorbType = {
      {512, "elementIce"},
      {1024, "elementHoly"},
      {2048, "elementDeath"}
   };

   // Access by index
   std::cout << "512->" << absorbType[512] << std::endl;

answered Feb 6, 2022 at 9:12

nielsen

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2 Comments

dohdle Over a year ago

I had the feeling it was pretty easy but had no clue how, thank you so much! Glad to learn something new

A M Over a year ago

It will make no difference here. But maybe we could also consider a std::unordered_map

Phillip Ngan · Accepted Answer · 2022-02-06 09:20:10Z

2

You can use a map which is the C++ implementation of a dictionary.

#include <iostream>
#include <map>
using namespace std;

int main()
{
    std::map<int, std::string> m { {512,  "elementIce" }, {1024,  "elementHoly"}, {2048, "elementDeath"}, };

    std::cout<< m[512] << std::endl;
    std::cout<< m[1024] << std::endl;
    std::cout<< m[2048] << std::endl;
    return 0;
}

answered Feb 6, 2022 at 9:20

Phillip Ngan

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2 Comments

Sebastian Over a year ago

using namespace std and prefixing with std:: are somehow redundant ...

Phillip Ngan Over a year ago

@Sebastian. You are right. I'll leave it there for illustration.

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