add: dfs test, and code fixes

samples/dfs.rpg

@@ -0,0 +1,68 @@
+**Free
+Ctl-Opt DftActGrp(*No) Main(MainLine);
+
+// --------------------------------------------------
+// Global Graph Data (15 Nodes)
+// --------------------------------------------------
+Dcl-S AdjMatrix Ind Dim(15: 15) Inz(*Off);
+Dcl-S Visited   Ind Dim(15)     Inz(*Off);
+Dcl-S Found     Ind             Inz(*Off);
+
+Dcl-Proc MainLine;
+    // 1. Setup a simple graph (Node 1 connected to 2 & 3, etc.)
+    AdjMatrix(1: 2) = *On; AdjMatrix(2: 4) = *On; AdjMatrix(4: 8) = *On;
+    AdjMatrix(1: 3) = *On; AdjMatrix(3: 5) = *On; AdjMatrix(5: 9) = *On; // Path to 9
+    AdjMatrix(3: 6) = *On; AdjMatrix(6: 10) = *On;
+
+    Dsply 'Starting DFS to find Node 9...';
+
+    // 2. Start Search from Node 1
+    DFS(1: 9);
+
+    If Not Found;
+        Dsply 'Node 9 was not found.';
+    EndIf;
+
+    Return;
+End-Proc;
+
+// --------------------------------------------------
+// Recursive DFS Subprocedure
+// --------------------------------------------------
+Dcl-Proc DFS;
+    Dcl-Pi *N;
+        CurrentNode Int(10) Value;
+        TargetNode  Int(10) Value;
+    End-Pi;
+
+    Dcl-S Neighbor Int(10);
+
+    // If already found elsewhere, stop exploring
+    If Found;
+        Return;
+    EndIf;
+
+    // Mark and Print current step
+    Visited(CurrentNode) = *On;
+    Dsply ('Visiting: ' + %Char(CurrentNode));
+
+    // Check if this is our target
+    If CurrentNode = TargetNode;
+        Dsply '*** MATCH FOUND! ***';
+        Found = *On;
+        Return;
+    EndIf;
+
+    // Explore Neighbors (1 to 15)
+    For Neighbor = 1 to 15;
+        If AdjMatrix(CurrentNode: Neighbor) And Not Visited(Neighbor);
+            DFS(Neighbor: TargetNode);
+
+            // If the recursive call found it, stop looping here too
+            If Found;
+                Return;
+            EndIf;
+        EndIf;
+    EndFor;
+
+End-Proc;