void prepare_distance_matrix()
{
unsigned int i, j;
double dist;
for (i = 0; i < N_CITIES; ++i) {
for (j = 0; j < N_CITIES; ++j) {
if (i == j) {
dist = 0;
} else {
dist = city_distance(cities[i], cities[j]);
}
distance_matrix[i][j] = dist;
}
}
}
// after calling this function, distances will be filled
// returns -1 on failure and 0 on success
int parse_input_file(char* input_file_path, int num_cities) {
int i, j;
char * this_line;
char buffer[100];
struct city* cities = (struct city*)calloc(num_cities, sizeof(struct city));
FILE *input_file = fopen(input_file_path, "rb");
if (input_file == NULL) {
perror ("The following error occurred");
return -1;
}
// skip header information
this_line = fgets(buffer, 100, input_file); // NAME
this_line = fgets(buffer, 100, input_file); // TYPE
this_line = fgets(buffer, 100, input_file); // COMMENT
this_line = fgets(buffer, 100, input_file); // DIMENSION
this_line = fgets(buffer, 100, input_file); // EDGE_WEIGHT_TYPE
this_line = fgets(buffer, 100, input_file); // NODE_COORD_SECTION
// read cities
for (i=0; i < num_cities; i++) {
this_line = fgets(buffer, 100, input_file);
sscanf(this_line, " %d %lf %lf",
&(cities[i].id_number),
&(cities[i].x_coord),
&(cities[i].y_coord)
);
}
// calculate and store distances and their inverses
for (i=0; i < num_cities; i++)
for (j=0; j < num_cities; j++)
distances[i][j] = city_distance(cities[i], cities[j]);
free(cities);
fclose(input_file);
return 0;
}
