From 61812932ac2eee40a79317682a72eae9bdb6d467 Mon Sep 17 00:00:00 2001
From: Imbus <>
Date: Mon, 27 May 2024 06:24:26 +0200
Subject: [PATCH] Initial

---
 Makefile     | 11 ++++----
 README.md    |  3 +++
 src/main.c   |  1 +
 src/main.cpp | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+), 5 deletions(-)
 create mode 100644 README.md
 create mode 100644 src/main.cpp

diff --git a/Makefile b/Makefile
index 91a48c6..34c2db3 100644
--- a/Makefile
+++ b/Makefile
@@ -1,24 +1,25 @@
 BIN := graphs
 # Compiler
-CC := gcc
+# CC := gcc
+CC := g++
 
 GITHASH := $(shell git rev-parse --short HEAD)
 
 # Compiler flags
-CFLAGS := -Wall -Wextra -Wpedantic -std=c2x
+CFLAGS := -Wall -Wextra -Wpedantic -std=c++23
 
 # Directories
 SRC_DIR := src
 BUILD_DIR := build
 
 # Source files
-SRCS := $(wildcard $(SRC_DIR)/*.c)
+SRCS := $(wildcard $(SRC_DIR)/*.cpp)
 
 # Header files (used for formatting)
 HEADERS := $(wildcard $(SRC_DIR)/*.h)
 
 # Object files
-OBJS := $(patsubst $(SRC_DIR)/%.c,$(BUILD_DIR)/%.o,$(SRCS))
+OBJS := $(patsubst $(SRC_DIR)/%.cpp,$(BUILD_DIR)/%.o,$(SRCS))
 
 # Target executable
 TARGET := $(BUILD_DIR)/$(BIN)
@@ -31,7 +32,7 @@ $(TARGET): $(OBJS)
 	$(CC) $(CFLAGS) $^ -o $@
 
 # Rule to build object files
-$(BUILD_DIR)/%.o: $(SRC_DIR)/%.c
+$(BUILD_DIR)/%.o: $(SRC_DIR)/%.cpp
 	@mkdir -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) -c $< -o $@
 
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..8c3bfe0
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+# Graphs
+
+Practice in writing different graph algorithms in C/C++
diff --git a/src/main.c b/src/main.c
index cda6155..312cd93 100644
--- a/src/main.c
+++ b/src/main.c
@@ -50,6 +50,7 @@ struct Graph* createGraph(int vertices) {
   struct Graph* graph = malloc(sizeof(struct Graph));
   graph->numVertices = vertices;
 
+  // Allocates a list with n*the size of a pointer, essentially
   graph->adjLists = malloc(vertices * sizeof(struct node*));
 
   graph->visited = malloc(vertices * sizeof(int));
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..11dfb7f
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,73 @@
+// DFS algorithm in C++
+
+#include <iostream>
+#include <list>
+using namespace std;
+
+// Interface for Expr
+class Expr {
+   public:
+    virtual void print() = 0;
+};
+
+class BinaryExpr : public Expr {
+   public:
+    BinaryExpr(Expr* lhs, Expr* rhs) : lhs(lhs), rhs(rhs) {}
+
+    void print() {
+        lhs->print();
+        rhs->print();
+    }
+
+   private:
+    Expr* lhs;
+    Expr* rhs;
+};
+
+class Graph {
+    int numVertices;
+    // Adjlist is a list of lists
+    list<int>* adjLists;
+    bool* visited;
+
+   public:
+    Graph(int V);
+    void addEdge(int src, int dest);
+    void DFS(int vertex);
+};
+
+// Initialize graph
+Graph::Graph(int vertices) {
+    numVertices = vertices;
+    // Note that this is creating 'vertices' number of lists
+    adjLists = new list<int>[vertices];
+    visited = new bool[vertices];
+}
+
+// Add edges
+void Graph::addEdge(int src, int dest) { adjLists[src].push_front(dest); }
+
+// DFS algorithm
+void Graph::DFS(int vertex) {
+    visited[vertex] = true;
+    // Get the list for this particular vertex
+    list<int> adjList = adjLists[vertex];
+
+    cout << vertex << " ";
+
+    list<int>::iterator i;
+    for (i = adjList.begin(); i != adjList.end(); ++i)
+        if (!visited[*i]) DFS(*i);
+}
+
+int main() {
+    Graph g(4);
+    g.addEdge(0, 1);
+    g.addEdge(0, 2);
+    g.addEdge(1, 2);
+    g.addEdge(2, 3);
+
+    g.DFS(2);
+
+    return 0;
+}