feat(tree): add C codes

codes/c/chapter_tree/binary_tree.c

@@ -0,0 +1,43 @@
+/**
+ * File: binary_tree.c
+ * Created Time: 2023-01-11
+ * Author: Reanon (793584285@qq.com)
+ */
+
+#include "../include/include.h"
+
+/* Driver Code */
+int main() {
+    /* 初始化二叉树 */
+    // 初始化结点
+    TreeNode* n1 = NewTreeNode(1);
+    TreeNode* n2 = NewTreeNode(2);
+    TreeNode* n3 = NewTreeNode(3);
+    TreeNode* n4 = NewTreeNode(4);
+    TreeNode* n5 = NewTreeNode(5);
+    // 构建引用指向（即指针）
+    n1->left = n2;
+    n1->right = n3;
+    n2->left = n4;
+    n2->right = n5;
+    printf("初始化二叉树\n");
+    PrintTree(n1);
+
+    /* 插入与删除结点 */
+    TreeNode* P = NewTreeNode(0);
+    // 在 n1 -> n2 中间插入结点 P
+    n1->left = P;
+    P->left = n2;
+    printf("插入结点 P 后\n");
+    PrintTree(n1);
+
+    // 删除结点 P
+    n1->left = n2;
+    // 释放内存
+    free(P);
+    printf("删除结点 P 后\n");
+    PrintTree(n1);
+
+    return 0;
+}
+