#include<stdio.h>
#include<stdlib.h>
#define MAX 100
#define initial 1
#define visited 2
int n; /*Number of vertices in the graph*/
int adj[MAX][MAX]; /*Adjacency Matrix*/
int state[MAX]; /*Can be initial or visited*/
void DF_Traversal();
void DFS(int v);
void create_graph();
int stack[MAX];
int top = -1;
void push(int v);
int pop();
int isEmpty_stack();
main()
{
create_graph();
DF_Traversal();
}/*End of main()*/
void DF_Traversal()
{
int v;
for(v=0; v=0; i--)
if(adj[v][i]==1 && state[i]==initial)
push(i);

}
}/*End of DFS( )*/
void push(int v)
{
if(top == (MAX-1))
{
printf("Stack Overflow\n");
return;
}
top = top+1;
stack[top] = v;
}/*End of push()*/
int pop()
{
int v;
if(top == -1)
{
printf("Stack Underflow\n");
exit(1);
}
else

{
v = stack[top];
top = top-1;
return v;
}
}/*End of pop()*/
int isEmpty_stack( )
{
if( top == -1)
return 1;
else
return 0;
}/*End if isEmpty_stack()*/
void create_graph()
{
int i,max_edges,origin,destin;
printf("Enter number of vertices : ");
scanf("%d",&n);
max_edges = n*(n-1);
for(i=1;i<=max_edges;i++)
{
printf("Enter edge %d( -1 -1 to quit ) : ",i);
scanf("%d %d",&origin,&destin);
if((origin == -1) && (destin == -1))
break;
if(origin >= n || destin >= n || origin<0 || destin<0)
{
printf("Invalid edge!\n");
i--;
}
else
{
adj[origin][destin] = 1;
}
}
}/*End of create_graph*/