added deapth_first_search

Searching/deapth_first_search.cpp

@@ -0,0 +1,45 @@
+
+#include<bits/stdc++.h>
+using namespace std;
+void dfs(int s, vector<int> g[], bool vis[])
+{   
+vector<int>::iterator i;
+    if(vis[s]==0){
+        cout<<s<<" ";
+        vis[s]=1;
+        for(i=g[s].begin();i!=g[s].end();i++){
+            if(vis[s]!=0){
+                dfs(*i,g,vis);
+            }
+        }
+    }
+
+}
+int main()
+{
+
+        int N, E;//number of vertices and number of edges
+        cin>>N>>E;
+
+        vector<int> g[N+1];
+        bool vis[N+1]={false};
+
+
+        for(int i=0;i<E;i++)
+        {
+            int u,v;
+            cin>>u>>v;
+            g[u].push_back(v);
+            g[v].push_back(u);
+        }
+        int startVertex;
+        cout<<"\nEnter the starting vertex from where you want to do dfs = ";
+        cin>>startVertex;
+        cout<<"\n";
+        dfs(startVertex,g,vis);
+
+        cout<<endl;
+}
+
+
+