ford.c

#include "ford.h"

static const int32_t INF = 2147483647;
void ford(int32_t *d, size_t V, edge *es, size_t E, size_t s) {
	for(int i = 0; i < V; i++)
		d[i] = INF;
	d[s] = 0;

	while(true) {
		bool update = false;
		for(int i = 0; i < E; i++) {
			edge e = es[i];
			if(d[e.from] != INF && d[e.from] + e.cost < d[e.to]) {
				update = true;
				d[e.to] = d[e.from] + e.cost;
			}
		}
		if(!update)
			break;
	}
}

ford.h

#include <stddef.h>
#include <stdbool.h>
#include <stdint.h>
#ifndef FORD_H
#define FORD_H

typedef struct _edge {
	size_t from, to;
	int32_t cost;
} edge;

void ford(int32_t *v, size_t V, edge *e, size_t E, size_t s);

#endif