Question

Say I have the following adjacency matrix:

  A B C D
A 0 9 0 5
B 9 0 0 0 
C 0 0 0 2
D 5 0 2 0

How would this acutally be implemented? I realize I can use a 2D array to represent the weighted edges between vertices but I’m not sure how to represent the vertices.

int edges[4][4];
string vertices[4];  

Is this the way to do it? The index in the vertices array corresponds to the row index in the edges array.

Answer 1

You can use a two dimensional std::map

Using this method allows for the matrix to grow and shrink when ever you want.

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

int main()
{
    std::map<std::string, std::map<std::string, int>> vertices;

    vertices["A"]["A"] = 0; vertices["A"]["B"] = 9; vertices["A"]["C"] = 0; vertices["A"]["D"] = 5;
    vertices["B"]["A"] = 9; vertices["B"]["B"] = 0; vertices["B"]["C"] = 0; vertices["B"]["D"] = 0;
    vertices["C"]["A"] = 0; vertices["C"]["B"] = 0; vertices["C"]["C"] = 0; vertices["C"]["D"] = 2;
    vertices["D"]["A"] = 5; vertices["D"]["B"] = 0; vertices["D"]["C"] = 2; vertices["D"]["D"] = 0;

    std::cout << vertices["A"]["A"] << std::endl;
    std::cout << vertices["A"]["B"] << std::endl;
}