Graph Traversal Implementation Using C - Adjacency List

Different graph traversals are
Breadth First Search
Depth First Search

Implementation 



/************************************************************
* Filename: graph_operations.c
* Description: To implement Graph Operations using Adjacency List
* Author: Sarju S
* Date: 03-Apr-2012
*************************************************************/
#include
#include
//Structure for Vertex Nodes
struct vertexNode{
int element;
int visited;
struct edgeNode *edge;
struct vertexNode *next;
};
typedef struct vertexNode vertexNode ;
vertexNode *start = NULL;


//Structure for Edge Nodes
struct edgeNode{
struct vertexNode *connectsTo;
struct edgeNode *next;
};
typedef struct edgeNode edgeNode ;
//Structure for Stack Nodes
struct stackNode
{
vertexNode *vElement;
struct stackNode *next;
};
typedef struct stackNode stackNode;
stackNode *top = NULL;


//Structure for Queue Nodes
struct queueNode
{
vertexNode *vElement;
struct queueNode *next;
};


typedef struct queueNode queueNode;
queueNode *qFront=NULL,*qRear=NULL;


//Function for creating new vertex node
void addVertex(int element){
vertexNode *newVertex,*temp;
//Allocating memory for new vertex node and initializing the values
newVertex = (vertexNode *) malloc(sizeof(vertexNode));
newVertex->element = element;
newVertex->visited =0;
newVertex->edge=NULL;
newVertex->next=NULL;
if(start==NULL){//If the graph is empty
start=newVertex;
}
else{//If the graph is not empty
temp= start;
while(temp->next!=NULL){
temp = temp->next;
}
temp->next = newVertex;
}
}


//Function for creating new edge node
void addEdge(int v1, int v2){
edgeNode *newEdge,*temp;
vertexNode *temp1,*v,*u;
temp1 = start;
/*Finding the source and destination vertex v is
the source vertex and u is the destination
vertex*/
while(temp1){
if(temp1->element == v1)
v=temp1;
if(temp1->element == v2)
u=temp1;
temp1=temp1->next;
}
newEdge = (edgeNode *) malloc(sizeof(edgeNode));
newEdge->connectsTo = u;
newEdge->next = NULL;
if(v->edge==NULL){
v->edge = newEdge;
}
else{
temp=v->edge;
while(temp->next!=NULL){
temp=temp->next;
}
temp->next=newEdge;
}

}


//Function for displaying the graph
void displayGraph(){
vertexNode *temp1;
edgeNode *temp2;
temp1=start;
while(temp1){
printf("%d->",temp1->element);
if(temp1->edge!=NULL){
temp2=temp1->edge;
while(temp2){
printf("%d->",temp2->connectsTo->element);
temp2=temp2->next;
}


}
printf("\n|\n");
printf("v\n");
temp1=temp1->next;

}

}
//Stack push function
void push(vertexNode *v){
stackNode *newStackNode;
newStackNode = (stackNode *) malloc(sizeof(stackNode));
newStackNode->vElement = v;
newStackNode->next = NULL;
if(top==NULL){
top=newStackNode;
}
else{
newStackNode->next = top;
top = newStackNode;
}


}
//Stack pop function
vertexNode * pop(){
vertexNode *temp=NULL;
if(top==NULL){
printf("\nStack is Empty");
}
else{
temp = top->vElement;
top = top->next;


}
return(temp);
}
//Function for Depth First Search
void dfs(){
vertexNode *temp;
edgeNode *temp2;
push(start);
while(top){
temp = pop();
if(temp->visited==0){
printf("%d\t",temp->element);
temp->visited = 1;
}
temp2=temp->edge;
while(temp2){
push(temp2->connectsTo);
temp2=temp2->next;
}
}
}
//Queue Insert function
void enQueue(vertexNode *v){
queueNode *tmp_ptr=NULL;
tmp_ptr=(queueNode *)malloc(sizeof(queueNode));
tmp_ptr->vElement = v;
tmp_ptr->next = NULL;
if(qFront == NULL){
qFront=tmp_ptr;
qRear=tmp_ptr;
}
else{
qRear->next=tmp_ptr;
qRear=tmp_ptr;
}

}


//Queue Delete function
vertexNode * deQueue(){
/*Delete element from Queue*/
vertexNode *temp=NULL;
temp = qFront->vElement;
if(qFront==NULL)
printf("\nThe Queue is Empty");
else if(qFront==qRear)
qFront=qRear=NULL;
else
qFront=qFront->next;

return(temp);

}
//Function for Breadth First Search
void bfs(){
vertexNode *temp;
edgeNode *temp2;
enQueue(start);
while(qFront){
temp =deQueue();
if(temp->visited==0){
printf("%d\t",temp->element);
temp->visited = 1;
}
temp2=temp->edge;
while(temp2){
enQueue(temp2->connectsTo);
temp2=temp2->next;
}
}
}
/*Function used for clering the visit tag of the
nodes to zero*/
void clearVisit(){
vertexNode *temp=start;
while(temp){
temp->visited =0;
temp=temp->next;
}
}


int main(){
int ch;
int element;
int v1,v2;
do{
printf("\n1:AddVertex\n2:AddEdge\n3:Dispaly\n4:DFS\n5:BFS\n6:Exit");
printf("\nEnter your choice:");
scanf("%d",&ch);
switch(ch){
case 1: printf("Entere the vertex to add:");
scanf("%d",&element);
addVertex(element);
break;
case 2: printf("\nEnter the vertices that are to be connected:");
scanf("%d%d",&v1,&v2);
addEdge(v1,v2);
break;
case 3: displayGraph();
break;
case 4: dfs();
clearVisit();
break;
case 5: bfs();
clearVisit();
}
}while(ch<6);
return 0;
}




OUTPUT

sjcet@sjcet-laptop:~$ gcc -Wall graph_operations.c
sjcet@sjcet-laptop:~$ ./a.out


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:0


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:1


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:2


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:3


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:4


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:5


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:6


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:7


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:1
Entere the vertex to add:8


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:2


Enter the vertices that are to be connected:0 1


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:2


Enter the vertices that are to be connected:0 2


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:2


Enter the vertices that are to be connected:1 3


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:2


Enter the vertices that are to be connected:2 4


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:2


Enter the vertices that are to be connected:3 5


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:2


Enter the vertices that are to be connected:4 6


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:2


Enter the vertices that are to be connected:4 7


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:2


Enter the vertices that are to be connected:4 8


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:3
0->1->2->
|
v
1->3->
|
v
2->4->
|
v
3->5->
|
v
4->6->7->8->
|
v
5->
|
v
6->
|
v
7->
|
v
8->
|
v


1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:4
0 2 4 8 7 6 1 3 5
1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:5
0 1 2 3 4 5 6 7 8
1:AddVertex
2:AddEdge
3:Dispaly
4:DFS
5:BFS
6:Exit
Enter your choice:6
sjcet@sjcet-laptop:~$ ./a.out