Are my structs set up correctly for adding cities (vertices) to an undirected weighted graph to find shortest path?

Question

Hello I've made a program to calculate the distances between two cities and now I want to use the data to map the cities on a undirected weighted graph. Then it will use Dikstra's Algorithm to find the shortest path. I'm trying out a adjacency list implementation because it seemed the right way but if another way is easier I'll do that. In some cases a city will have three neighbors.

This is the file I'm reading from, distances.txt: I was having a little trouble reading in city names with two words so I assigned them a integer ID but will probably change it later once I figure that out.

//The first integer is city1 and the second integer is city2 followed by the 
//distance between the two
0 1 11541.187059  
2 3 3858.222989
4 5 833.098012
6 7 20014.000000
8 9 13960.338459
10 11 13468.406555

This is my program:

#include <stdio.h>


typedef struct vertex vertex;
typedef struct edge edge;

struct vertex
{
    int ID;
    vertex* successor;
    vertex* predecessor;
};

struct edge
{
    double weight;
    vertex* vertexA;
    vertex* vertexB;
};


int main() {


    char line[256];
    FILE *fin = fopen("distances.txt","r"); 
    FILE *fout = fopen("shortest.txt","w"); 

    int c1,c2;
    double distance;

    vertex *city1,*city2; 

    while ( fscanf (fin, "%d %d %lf", &c1,&c2,&distance)== 3)
    {   
        printf("[City1: %d] [City2: %d] [Distance: %lf]\n",c1,c2,distance); 
        city1->ID = c1; 
        city2->ID = c2; 
        city1->successor = city2; 
        city2->predecessor = city1; 

    }

    return 0; 

}

void addEdge(vertex* x,vertex* y, double weight){
    edge* m; 
    m = malloc (sizeof(edge)); 
    m->weight = weight; 
    m->vertexA = x;
    m->vertexB = y; 

}

void shortestPath() {

}

Answer 1

If your strcuture should only represent the shortest path, then it shoul dbe ok. If you need to represent the graph with it, then I don't see how you can represent it, because edges can have multiple edges connecting each other. So you would need an array and a counter to keep track of the edges per vertex.