BFS and DFS using C

BFS_DFS.C

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+#include<stdio.h>
+
+int q[20],top=-1,front=-1,rear=-1,a[20][20],vis[20],stack[20];
+int delete();
+void add(int item);
+void bfs(int s,int n);
+void dfs(int s,int n);
+void push(int item);
+int pop();
+
+void main()
+{
+int n,i,s,ch,j;
+char c,dummy;
+printf("ENTER THE NUMBER VERTICES ");
+scanf("%d",&n);
+for(i=1;i<=n;i++)
+{
+for(j=1;j<=n;j++)
+{
+printf("ENTER 1 IF %d HAS A NODE WITH %d ELSE 0 ",i,j);
+scanf("%d",&a[i][j]);
+}
+}
+printf("THE ADJACENCY MATRIX IS\n");
+for(i=1;i<=n;i++)
+{
+for(j=1;j<=n;j++)
+{
+printf(" %d",a[i][j]);
+}
+printf("\n");
+}
+
+do
+{
+for(i=1;i<=n;i++)
+vis[i]=0;
+printf("\nMENU");
+printf("\n1.B.F.S");
+printf("\n2.D.F.S");
+printf("\nENTER YOUR CHOICE");
+scanf("%d",&ch);
+printf("ENTER THE SOURCE VERTEX :");
+scanf("%d",&s);
+
+switch(ch)
+{
+case 1:bfs(s,n);
+break;
+case 2:
+dfs(s,n);
+break;
+}
+printf("DO U WANT TO CONTINUE(Y/N) ? ");
+scanf("%c",&dummy);
+scanf("%c",&c);
+}while((c=='y')||(c=='Y'));
+}
+
+
+//**************BFS(breadth-first search) code**************//
+void bfs(int s,int n)
+{
+int p,i;
+add(s);
+vis[s]=1;
+p=delete();
+if(p!=0)
+printf(" %d",p);
+while(p!=0)
+{
+for(i=1;i<=n;i++)
+if((a[p][i]!=0)&&(vis[i]==0))
+{
+add(i);
+vis[i]=1;
+}
+p=delete();
+if(p!=0)
+printf(" %d ",p);
+}
+for(i=1;i<=n;i++)
+if(vis[i]==0)
+bfs(i,n);
+}
+
+
+void add(int item)
+{
+if(rear==19)
+printf("QUEUE FULL");
+else
+{
+if(rear==-1)
+{
+q[++rear]=item;
+front++;
+}
+else
+q[++rear]=item;
+}
+}
+int delete()
+{
+int k;
+if((front>rear)||(front==-1))
+return(0);
+else
+{
+k=q[front++];
+return(k);
+}
+}
+
+
+//***************DFS(depth-first search) code******************//
+void dfs(int s,int n)
+{
+int i,k;
+push(s);
+vis[s]=1;
+k=pop();
+if(k!=0)
+printf(" %d ",k);
+while(k!=0)
+{
+for(i=1;i<=n;i++)
+if((a[k][i]!=0)&&(vis[i]==0))
+{
+push(i);
+vis[i]=1;
+}
+k=pop();
+if(k!=0)
+printf(" %d ",k);
+}
+for(i=1;i<=n;i++)
+if(vis[i]==0)
+dfs(i,n);
+}
+void push(int item)
+{
+if(top==19)
+printf("Stack overflow ");
+else
+stack[++top]=item;
+}
+int pop()
+{
+int k;
+if(top==-1)
+return(0);
+else
+{
+k=stack[top--];
+return(k);
+}
+}