Some helper functions for building and traversing a graph in c.

graphHelpers.c

#include <stdlib.h>

typedef struct Edge Edge;
typedef struct Node Node;
Edge* EdgewithNodes(Node* src, Node* dest);
Node* NodewithInfo(int i);
Node* createNodes(int i, int left);
void addEdge(Edge* src, Edge* new);
void addEdgetoNode(Node* src, Node* dest);

// Node type
struct Node {
	Edge* firstEdge;
	Node* nextNode;
	int info;
};

// Edge type
struct Edge {
	Node* srcNode;
	Node* destNode;
	Edge* nextEdge;
};

Node* NodewithInfo(int i) {
	Node* n = malloc(sizeof(Node));
	n->info = i;
	n->firstEdge = NULL;
	n->nextNode = NULL;
	return n;
}

Edge* EdgewithNodes(Node* src, Node* dest) {
	Edge* e = malloc(sizeof(Edge));
	e->srcNode = src;
	e->destNode = dest;
	e->nextEdge = NULL;
	return e;
}

//Global variable's are not best practice but we're writing this kinda fast.
Node Head;

Node* createNodes(int i, int left) {
	Node* newNode = NodewithInfo(i);
	if (left == 1) {
		return newNode;
	} else {
		newNode->nextNode = createNodes(i + 1, left - 1);
		return newNode;
	}
}

void addEdge(Edge* src, Edge* new) {
	if (src-> nextEdge == NULL) {
		src->nextEdge = new;
		return;
	} else {
		return addEdge(src->nextEdge, new);
	}
}

void addEdgetoNode(Node* src, Node* dest) {
	Edge* newEdge = EdgeWithNodes(src, dest);
	if (src->firstEdge == NULL) {
		src->firstEdge = newEdge;
		return;
	} else {
		return adddEdge(src->firstEdge, newEdge);
	}
}