diff --git a/assignment/C/lixinyi/work2 b/assignment/C/lixinyi/work2
new file mode 100644
index 0000000000000000000000000000000000000000..daff2d29209f3419b71bb90b4c57cebc8f18d2ad
--- /dev/null
+++ b/assignment/C/lixinyi/work2
@@ -0,0 +1,111 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <assert.h>
+
+typedef double (*func_t)(double);
+
+// 返回funcs中所有函数的复合函数，即f(x) = fn(...f2(f1(x)))
+double composite(func_t funcs[],int n,double input)
+{
+	double result = input;
+	for(int i=0;i<n;i++){
+		result = funcs[i](result);
+	} 
+	return result;
+}
+
+
+void check1()
+{
+	double (*test1[3])(double) = {sin,cos,exp};
+	assert(fabs(composite(test1,3,0.5) - 2.428467) < 1e-6);
+	double (*test2[4])(double) = {log,sin,cos,exp};
+	assert(fabs(composite(test2,4,1) - 2.718282) < 1e-6);
+}
+
+// 二叉树节点
+struct Node{
+	int val;	// 节点值
+	struct Node *left;	// 左儿子
+	struct Node *right; // 右儿子
+};
+
+// 使用malloc创建一个节点，并初始化节点
+struct Node *newNode(int val)
+{
+	struct Node*node=(struct Node*)malloc(sizeof(struct Node));
+	node->val=val;
+	node->left=NULL;
+	node->right=NULL;
+	return node;
+}
+
+// 插入一个节点，如果val比当前节点值小，插入左子树，否则插入右子树
+void insert(struct Node *root, int val)
+{
+	if(val<root->val){
+		if(root->left==NULL){
+			root->left=newNode(val);
+		}
+		else{
+			insert(root->left,val); 
+		}
+	}
+	else{
+		if(root->right==NULL){
+			root->right=newNode(val); 
+		}
+		else{
+			insert(root->right,val); 
+		}
+	}
+}
+
+// 遍历二叉树，先遍历左儿子，然后遍历自己，最后遍历右儿子，将遍历结果存入数组中，返回数组长度
+int traverse(struct Node *root, int *arr)
+{
+	if(root==NULL){
+		return 0;
+	}
+	int left_len=traverse(root->left,arr);
+	arr[left_len]=root->val;
+	int right_len=traverse(root->right,arr+left_len+1);
+	return left_len+right_len+1;
+}
+
+// 释放二叉树的内存
+void freeTree(struct Node *root)
+{
+	if(root==NULL){
+		return;
+	}
+	freeTree(root->left);
+	freeTree(root->right);
+	free(root);
+}
+
+void check2()
+{
+	struct Node *root = newNode(5);
+	insert(root, 3);
+	insert(root, 7);
+	insert(root, 2);
+	insert(root, 4);
+	insert(root, 6);
+	insert(root, 8);
+	int arr[7];
+	int len = traverse(root, arr);
+	assert(len == 7);
+	for (int i = 0; i < len; i++)
+		assert(arr[i] == i + 2);
+	freeTree(root);
+}
+
+int main()
+{
+	check1();
+	check2();
+	puts("Tests passed!");
+	return 0;
+}
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