#include<graphviz/cgraph.h>
#include<graphviz/gvc.h>
#include<stdio.h>

int main(){
	Agraph_t *g;
	g = agopen("G", Agdirected, 0);
	Agnode_t *a = agnode(g, "Apple", 1);
	Agnode_t *b = agnode(g, "B", 1);
	Agnode_t *c = agnode(g, "C", 1);
	Agnode_t *d = agnode(g, "D", 1);
	Agnode_t *e = agnode(g, "E", 1);
	Agnode_t *f = agnode(g, "F", 1);

	agedge(g, a, b, "Bob", 1);
	agedge(g, a, c, "", 1);
	agedge(g, c, f, "", 1);
	agedge(g, b, d, "", 1);
	agedge(g, b, e, "", 1);

	agwrite(g, stdout);

	GVC_t* gvc = gvContext();
	gvLayout(gvc, g, "dot");
	gvRenderFilename(gvc, g, "png", "out.png");
	gvFreeLayout(gvc, g);
	agclose(g);
	
	return 0;
}
/* To build this program:
gcc graph_demo.c -lcgraph -lgvc

If there's an error about missing header files, maybe libgraphviz-dev isn't installed:
sudo apt install libgraphviz-dev
*/