add function.md

en/src/basic-types/functions.md

@@ -1 +1,43 @@
 # Functions
+🌟🌟🌟
+```rust,editable
+
+fn main() {
+    // don't modify the following two lines!
+    let (x, y) = (1, 2);
+    let s = sum(1, 2);
+
+    assert_eq!(s, 3);
+}
+
+fn sum(x, y: i32) {
+    x + y;
+}
+```
+
+
+🌟🌟
+```rust,editable
+fn main() {
+   print();
+}
+
+// replace i32 with another type
+fn print() -> i32 {
+   println!("hello,world");
+}
+```
+
+
+🌟🌟
+
+```rust,editable
+fn main() {
+    never_return();
+}
+
+fn never_return() -> ! {
+    // implement this function, don't modify fn signatures
+    
+}
+```

zh-CN/src/basic-types/functions.md

@@ -1 +1,43 @@
-# Functions
+# 函数
+🌟🌟🌟
+```rust,editable
+
+fn main() {
+    // 不要修改下面两行代码!
+    let (x, y) = (1, 2);
+    let s = sum(1, 2);
+
+    assert_eq!(s, 3);
+}
+
+fn sum(x, y: i32) {
+    x + y;
+}
+```
+
+
+🌟🌟
+```rust,editable
+fn main() {
+   print();
+}
+
+// 使用另一个类型来替代 i32
+fn print() -> i32 {
+   println!("hello,world");
+}
+```
+
+
+🌟🌟
+
+```rust,editable
+fn main() {
+    never_return();
+}
+
+fn never_return() -> ! {
+    // 实现这个函数，不要修改函数签名!
+    
+}
+```