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Sets and Maps

Apr 23, 2024, 1 min read

Sets are a collection of objects:

  • They might be ordered or unordered.
  • Two variants:
    1. Single instance of any object.
    2. Multiple instances.

Maps associate a value or values with a key:

  • They might be ordered or unordered.
  • Two variants:
    1. Single value per key.
    2. Multiple values per key.

Example:

#include <map>
 
std::map<size_t, std::string> map;
 
map[0] = "Hello";
map[1] = "you";
map[2] = "there!";

Example in C++:

#include <map>
#include <string>
using namespace std;
 
int main() {
  map<int, string> sample_map;
  sample_map.insert(pair<int, string>(1, "one"));
  sample_map.insert(pair<int, string>(2, "two"));
 
  cout << sample_map[1] << " " << sample_map[2] << endl;
}

Another example but needs C++11:

#include <iostream>
#include <map>
#include <string>
using namespace std;
 
int main() {
  map<int, string> sample_map { { 1, "one"}, { 2, "two" } };
 
  cout << sample_map[1] << " " << sample_map[2] << endl;
}
C++ has great built-in support for these, C does not.

Resources

C++ Maps Explained

Graph View

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