traversal

Author: Shahid6174

graph_traversal.c

@@ -0,0 +1,98 @@
+//Will work only for graphs with no self loops
+
+#include <stdio.h>
+
+void bfs(int n, int a[20][20], int source, int visited[20], int e[20][2])
+{
+    int f=0, r=-1, q[20];
+    int u, v, k = 1;
+    visited[source] = 1;
+    r += 1;
+    q[r] = source;
+    while(f<=r)
+    {
+        u = q[f];
+        f = f+1;
+        for(v=1; v<=n; v++)
+        {
+            if(a[u][v]==1 && visited[v]==0)
+            {
+                visited[v] = 1;
+                r += 1;
+                q[r] = v;
+                e[k][1] = u;
+                e[k][2] = v;
+                k = k+1;
+            }
+        }     
+    }
+
+}
+
+void dfs(int n, int a[20][20], int u, int visited[20], int e[20][2])
+{
+    int v;
+    static int k = 1;
+    visited[u] = 1;
+    for(v=1; v<=n; v++)
+    {
+        if(a[u][v] == 1 && visited[v] == 0)
+        {
+            e[k][1] = u;
+            e[k][2] = v;
+            k = k+1;
+            dfs(n,a,v,visited,e);
+        }
+    }
+}
+
+int main()
+{
+    int i, j, n, visited[20], a[20][20], source, flag=0, choice, e[20][2];
+    printf("Enter the number of vertices: ");
+    scanf("%d", &n);
+    printf("Enter the adjacency matrix: \n");
+    for(i = 1; i<=n; i++)
+    {
+        for(j = 1; j<=n; j++)
+        {
+            scanf("%d", &a[i][j]);
+        }
+    }
+    printf("Enter the source node: ");
+    scanf("%d", &source);
+    for(i=1; i<=n; i++)
+    {
+        visited[i] = 0;
+    }
+
+    printf("Enter 1.BFS 2.DFS: ");
+    scanf("%d", &choice);
+    if(choice == 1)
+        bfs(n, a, source, visited, e);
+    else
+        dfs(n, a, source, visited,e);
+    
+    for(i=1; i<=n; i++)
+    {
+        if(visited[i] == 0)
+        {
+            flag = 1;
+            printf("%d is not reachable.\n",i);
+        }
+        else
+            printf("%d is reachable.\n", i);
+    }
+    if(flag == 1)
+    {
+        printf("Graph is not connected.\n");
+    }
+    else
+    {
+        printf("It is a connected graph.\n");
+        printf("The Spanning tree is: \n");
+        for(i = 1; i<=n-1; i++)
+            printf("%d to %d\n",e[i][1],e[i][2]);
+    }
+    return 0 ;
+}