FindPath.c

// Jevin Olano
// jolano
// CSE 101
// November 22, 2019
// FindPath.c

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "Graph.h"
#include "List.h"

int main (int argc, char* argv[]) {

	if (argc != 3) {
		fprintf(stderr, "Usage %s <input> <output>\n", argv[0]);
		exit(1);
	}

	FILE *in = fopen(argv[1], "r");
	FILE *out = fopen(argv[2], "w");

	if (in == NULL) {
		printf("Unable to read from file %s\n", argv[1]);
    	exit(1);
	}
	if (out == NULL) {
		printf("Unable to write to file %s\n", argv[2]);
    	exit(1);
	}

	int n = 0; // for newGraph(n) later
	fscanf(in, "%d", &n);

	Graph G = newGraph(n); // creates a new Graph object
	int tempSource = 0; // temp source vertex for addEdge()
	int tempDest = 0; // temp destination vertex for addEdge()
	int source = 0; // source for BFS algorithm
	int destination = 0; // destination for BFS algorithm

	while (fgetc(in) != EOF) { // EOF = end of file, recognized by C
		fscanf(in, "%d", &tempSource);
		fscanf(in, "%d", &tempDest);
		if (tempSource == 0 && tempDest == 0) {
			break;
		}
		addEdge(G, tempSource, tempDest);
	}
	printGraph(out, G);
	fprintf(out, "\n");

	while (fgetc(in) != EOF) { // EOF = end of file, recognized by C

		fscanf(in, "%d", &source);
		fscanf(in, "%d", &destination);
		if (source == 0 && destination == 0) {
			break;
		}
		List L = newList();
		BFS(G, source);
		getPath(L, G, destination);

		if (getDist(G, destination) != INF) {
			fprintf(out, "The distance from %d to %d is %d\n", source, destination, length(L) - 1);
			fprintf(out, "A shortest %d-%d path is: ", source, destination);
			printList(out, L);
			fprintf(out, "\n\n");
		} else {
			fprintf(out, "The distance from %d to %d is infinity\n", source, destination);
			fprintf(out, "No %d-%d path exists\n\n", source, destination);
		}
		freeList(&L);
	}

	freeGraph(&G);
	fclose(in);
	fclose(out);
	return EXIT_SUCCESS;
}