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Editorial Team
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Asked: 2026-06-17T02:00:34+00:00

How will you design a table datastructure for lookup? I basically have to represent

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How will you design a table datastructure for lookup?

I basically have to represent the following table

Country             Activity        Legal_Age
European            Drink           18
European            Drive           21
American            Drink           21
American            Drive           18

Here my Key is (Country & Activity) and the value is Legal_age.

I thought of using std::map to breakdown this problem (into individual maps) as follows.

national_Activity_age_map

European            European_Activity_age_map
American            American_Activity_age_map

European_Activity_age_map

Drink           18
Drive           21

American_Activity_age_map

Drink           21
Drive           18

But the problem here is, as the number of columns to the original table keeps growing, the number of maps to be added and maintained keeps growing.

Let’s say the US chooses to have seperate drinking ages for US-citizens and non-citizens. Then I will have to add new mappings and also modify existing mappings.

Is there a simple & a clean way to represent this data in a DataStructure which takes in a multiple factored Key and produce one value?

There are a few similar questions like below but nothing answers my specific problem.
What datastructure would you use to represent this format of data?

Update:
I can’t use Boost features at work since it has to be ported (or something like that). Is there a C++ (gcc 4.1.2) feature that I can use.

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1 Answer

  1. Editorial Team

    Try Boost Multi-Index.

    The Boost Multi-index Containers Library provides a class template named multi_index_container which enables the construction of containers maintaining one or more indices with different sorting and access semantics. Indices provide interfaces similar to those of STL containers, making using them familiar. The concept of multi-indexing over the same collection of elements is borrowed from relational database terminology and allows for the specification of complex data structures in the spirit of multiply indexed relational tables where simple sets and maps are not enough.

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