diff --git a/3_lesson/01_fun/.gitignore b/3_lesson/01_fun/.gitignore
new file mode 100644
index 0000000..fab7372
--- /dev/null
+++ b/3_lesson/01_fun/.gitignore
@@ -0,0 +1,73 @@
+# This file is used to ignore files which are generated
+# ----------------------------------------------------------------------------
+
+*~
+*.autosave
+*.a
+*.core
+*.moc
+*.o
+*.obj
+*.orig
+*.rej
+*.so
+*.so.*
+*_pch.h.cpp
+*_resource.rc
+*.qm
+.#*
+*.*#
+core
+!core/
+tags
+.DS_Store
+.directory
+*.debug
+Makefile*
+*.prl
+*.app
+moc_*.cpp
+ui_*.h
+qrc_*.cpp
+Thumbs.db
+*.res
+*.rc
+/.qmake.cache
+/.qmake.stash
+
+# qtcreator generated files
+*.pro.user*
+
+# xemacs temporary files
+*.flc
+
+# Vim temporary files
+.*.swp
+
+# Visual Studio generated files
+*.ib_pdb_index
+*.idb
+*.ilk
+*.pdb
+*.sln
+*.suo
+*.vcproj
+*vcproj.*.*.user
+*.ncb
+*.sdf
+*.opensdf
+*.vcxproj
+*vcxproj.*
+
+# MinGW generated files
+*.Debug
+*.Release
+
+# Python byte code
+*.pyc
+
+# Binaries
+# --------
+*.dll
+*.exe
+
diff --git a/3_lesson/01_fun/01_fun.pro b/3_lesson/01_fun/01_fun.pro
new file mode 100644
index 0000000..fc18d89
--- /dev/null
+++ b/3_lesson/01_fun/01_fun.pro
@@ -0,0 +1,6 @@
+TEMPLATE = app
+CONFIG += console
+CONFIG -= app_bundle
+CONFIG -= qt
+
+SOURCES += main.c
diff --git a/3_lesson/01_fun/main.c b/3_lesson/01_fun/main.c
new file mode 100644
index 0000000..1a12753
--- /dev/null
+++ b/3_lesson/01_fun/main.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+
+// 定义一个没有参数也没有返回值的函数
+void myfun1()
+{
+    printf("hello world\n");
+    printf("nihao beijing\n");
+    printf("welcome to 1000phone\n");
+
+    return;
+}
+
+// 定义一个有参数的函数
+void myfun2(int a, int b)
+{
+    int sum;
+    sum = a + b;
+
+    printf("%d + %d = %d\n", a, b, sum);
+}
+
+// 定义一个有返回值的函数
+int myfun3(int a, int b)
+{
+    int sum;
+    sum = a + b;
+
+    return sum;
+}
+
+int main(int argc, char *argv[])
+{
+    // 函数的调用
+    // 函数在调用的时候如果没有参数，也必须加括号
+    // 函数调用的时候不能加返回值类型
+    myfun1();
+
+    return 0;
+}
diff --git a/课件/第3章_函数_笔记.pdf b/课件/第3章_函数_笔记.pdf
new file mode 100644
index 0000000..3a3133e
Binary files /dev/null and b/课件/第3章_函数_笔记.pdf differ