diff --git a/LICENSE b/LICENSE
index 1317289..f49a4e1 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,21 +1,201 @@
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-Copyright (c) 2022 Sunface.
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\ No newline at end of file
diff --git a/solutions/formatted-output/formatting.md b/solutions/formatted-output/formatting.md
new file mode 100644
index 0000000..2115615
--- /dev/null
+++ b/solutions/formatted-output/formatting.md
@@ -0,0 +1,140 @@
+1.
+```rust
+fn main() {
+ println!("{0}, this is {1}. {1}, this is {0}", "Alice", "Bob");// => Alice, this is Bob. Bob, this is Alice
+ assert_eq!(format!("{1}{0}", 1, 2), "21");
+ assert_eq!(format!("{1}{}{0}{}", 1, 2), "2112");
+ println!("Success!")
+}
+```
+
+2.
+```rust
+fn main() {
+ println!("{argument}", argument = "test"); // => "test"
+
+ assert_eq!(format!("{name}{}", 1, name = 2), "21");
+ assert_eq!(format!("{a} {c} {b}",a = "a", b = 'b', c = 3 ), "a 3 b");
+
+ // named argument must be placed after other arguments
+ println!("{abc} {0}", 2, abc = "def");
+
+ println!("Success!")
+}
+```
+
+3.
+```rust
+fn main() {
+ // the following two are padding with 5 spaces
+ println!("Hello {:5}!", "x"); // => "Hello x !"
+ println!("Hello {:1$}!", "x", 5); // => "Hello x !"
+
+ assert_eq!(format!("Hello {1:0$}!", 5, "x"), "Hello x !");
+ assert_eq!(format!("Hello {:width$}!", "x", width = 5), "Hello x !");
+
+ println!("Success!")
+}
+```
+
+4.
+```rust
+fn main() {
+ // left align
+ println!("Hello {:<5}!", "x"); // => Hello x !
+ // right align
+ assert_eq!(format!("Hello {:>5}!", "x"), "Hello x!");
+ // center align
+ assert_eq!(format!("Hello {:^5}!", "x"), "Hello x !");
+
+ // left align, pad with '&'
+ assert_eq!(format!("Hello {:&<5}!", "x"), "Hello x&&&&!");
+
+ println!("Success!")
+}
+```
+
+5.
+```rust
+fn main() {
+ println!("Hello {:5}!", 5); // => Hello 5!
+ println!("Hello {:+}!", 5); // => Hello +5!
+ println!("Hello {:05}!", 5); // => Hello 00005!
+ println!("Hello {:05}!", -5); // => Hello -0005!
+
+ assert!(format!("{number:0>width$}", number=1, width=6) == "000001");
+
+ println!("Success!")
+}
+```
+
+6.
+```rust
+fn main() {
+ let v = 3.1415926;
+
+ println!("{:.1$}", v, 4); // same as {:.4} => 3.1416
+
+ assert_eq!(format!("{:.2}", v), "3.14");
+ assert_eq!(format!("{:+.2}", v), "+3.14");
+ assert_eq!(format!("{:.0}", v), "3");
+
+ println!("Success!")
+}
+```
+
+7.
+```rust
+fn main() {
+ let s = "Hello, world!";
+
+ println!("{0:.5}", s); // => Hello
+
+ assert_eq!(format!("Hello {1:.0$}!", 3, "abcdefg"), "Hello abc!");
+
+ println!("Success!")
+}
+```
+
+8.
+```rust
+fn main() {
+ assert_eq!(format!("{:#b}", 27), "0b11011");
+ assert_eq!(format!("{:#o}", 27), "0o33");
+ assert_eq!(format!("{:#x}", 27), "0x1b");
+ assert_eq!(format!("{:#X}", 27), "0x1B");
+
+ println!("{:x}!", 27); // hex with no prefix => 1b
+
+ println!("{:#010b}", 27); // pad binary with 0, width = 10, => 0b00011011
+
+ println!("Success!")
+}
+```
+
+9.
+```rust
+fn get_person() -> String {
+ String::from("sunface")
+}
+
+fn get_format() -> (usize, usize) {
+ (4, 1)
+}
+
+
+fn main() {
+ let person = get_person();
+ println!("Hello, {person}!");
+
+ let (width, precision) = get_format();
+ let scores = [("sunface", 99.12), ("jack", 60.34)];
+ /* Make it print:
+ sunface: 99.1
+ jack: 60.3
+ */
+ for (name, score) in scores {
+ println!("{name}: {score:width$.precision$}");
+ }
+}
+```
\ No newline at end of file
diff --git a/src/formatted-output/formatting.md b/src/formatted-output/formatting.md
index 76c191f..b68a06e 100644
--- a/src/formatted-output/formatting.md
+++ b/src/formatted-output/formatting.md
@@ -1 +1,183 @@
# formating
+
+## Positional arguments
+
+1.๐๐
+```rust,edtiable
+
+/* Fill in the blanks */
+fn main() {
+ println!("{0}, this is {1}. {1}, this is {0}", "Alice", "Bob");// => Alice, this is Bob. Bob, this is Alice
+ assert_eq!(format!("{1}{0}", 1, 2), __);
+ assert_eq!(format!(__, 1, 2), "2112");
+ println!("Success!");
+}
+```
+
+## Named arguments
+
+2.๐๐
+```rust,editable
+fn main() {
+ println!("{argument}", argument = "test"); // => "test"
+
+ /* Fill in the blanks */
+ assert_eq!(format!("{name}{}", 1, __), "21");
+ assert_eq!(format!(__,a = "a", b = 'b', c = 3 ), "a 3 b");
+
+ /* Fix the error */
+ // named argument must be placed after other arguments
+ println!("{abc} {1}", abc = "def", 2);
+
+ println!("Success!")
+}
+```
+
+## Padding with string
+
+3.๐๐ By default, you can pad string with spaces
+```rust,editable
+fn main() {
+ // the following two are padding with 5 spaces
+ println!("Hello {:5}!", "x"); // => "Hello x !"
+ println!("Hello {:1$}!", "x", 5); // => "Hello x !"
+
+ /* Fill in the blanks */
+ assert_eq!(format!("Hello __!", 5, "x"), "Hello x !");
+ assert_eq!(format!("Hello __!", "x", width = 5), "Hello x !");
+
+ println!("Success!")
+}
+```
+
+4.๐๐๐ Left align, right align, pad with specified characters.
+```rust,editable
+fn main() {
+ // left align
+ println!("Hello {:<5}!", "x"); // => Hello x !
+ // right align
+ assert_eq!(format!("Hello __!", "x"), "Hello x!");
+ // center align
+ assert_eq!(format!("Hello __!", "x"), "Hello x !");
+
+ // left align, pad with '&'
+ assert_eq!(format!("Hello {:&<5}!", "x"), __);
+
+ println!("Success!")
+}
+```
+
+5.๐๐ You can pad numbers with extra zeros.
+```rust,editable
+fn main() {
+ println!("Hello {:5}!", 5); // => Hello 5!
+ println!("Hello {:+}!", 5); // => Hello +5!
+ println!("Hello {:05}!", 5); // => Hello 00005!
+ println!("Hello {:05}!", -5); // => Hello -0005!
+
+ /* Fill in the blank */
+ assert!(format!("{number:0>width$}", number=1, width=6) == __);
+
+ println!("Success!")
+}
+```
+
+## precision
+6.๐๐ Floating point precision
+```rust,editable
+
+/* Fill in the blanks */
+fn main() {
+ let v = 3.1415926;
+
+ println!("{:.1$}", v, 4); // same as {:.4} => 3.1416
+
+ assert_eq!(format!("__", v), "3.14");
+ assert_eq!(format!("__", v), "+3.14");
+ assert_eq!(format!("__", v), "3");
+
+ println!("Success!")
+}
+```
+
+7.๐๐๐ string length
+```rust,editable
+fn main() {
+ let s = "Hello, world!";
+
+ println!("{0:.5}", s); // => Hello
+
+ assert_eq!(format!("Hello __!", 3, "abcdefg"), "Hello abc!");
+
+ println!("Success!")
+}
+```
+
+## binary, octal, hex
+
+- format!("{}", foo) -> "3735928559"
+- format!("0x{:X}", foo) -> "0xDEADBEEF"
+- format!("0o{:o}", foo) -> "0o33653337357"
+
+8.๐๐
+```rust,editable
+fn main() {
+ assert_eq!(format!("__", 27), "0b11011");
+ assert_eq!(format!("__", 27), "0o33");
+ assert_eq!(format!("__", 27), "0x1b");
+ assert_eq!(format!("__", 27), "0x1B");
+
+ println!("{:x}!", 27); // hex with no prefix => 1b
+
+ println!("{:#010b}", 27); // pad binary with 0, width = 10, => 0b00011011
+
+ println!("Success!")
+}
+```
+
+## Capture the enviroments
+9.๐๐๐
+```rust,editable
+fn get_person() -> String {
+ String::from("sunface")
+}
+
+fn get_format() -> (usize, usize) {
+ (4, 1)
+}
+
+
+fn main() {
+ let person = get_person();
+ println!("Hello, {person}!");
+
+ let (width, precision) = get_format();
+ let scores = [("sunface", 99.12), ("jack", 60.34)];
+ /* Make it print:
+ sunface: 99.1
+ jack: 60.3
+ */
+ for (name, score) in scores {
+ println!("{name}: __");
+ }
+}
+```
+
+
+## Others
+
+**Example**
+```rust,editable
+fn main() {
+ // exponent
+ println!("{:2e}", 1000000000); // => 1e9
+ println!("{:2E}", 1000000000); // => 1E9
+
+ // pointer address
+ let v= vec![1, 2, 3];
+ println!("{:p}", v.as_ptr()); // => 0x600002324050
+
+ // escape
+ println!("Hello {{}}"); // => Hello {}
+}
+```
\ No newline at end of file
diff --git a/src/why-exercise.md b/src/why-exercise.md
index 66dbf81..6051eb1 100644
--- a/src/why-exercise.md
+++ b/src/why-exercise.md
@@ -1,5 +1,5 @@
-
+
Practice Rust with challenging examples, exercises and projects
diff --git a/zh-CN/src/why-exercise.md b/zh-CN/src/why-exercise.md
index 00a134e..d843757 100644
--- a/zh-CN/src/why-exercise.md
+++ b/zh-CN/src/why-exercise.md
@@ -1,5 +1,5 @@
-
+
้่ฟๆๆๆๆง็็คบไพใ็ปไน ้ขใๅฎ่ทต้กน็ฎๆฅๆๅ Rust ๆฐดๅนณ๏ผๅปบ็ซไปๅ
ฅ้จๅญฆไน ๅฐไธๆๅฎๆ็็ด้ๆกฅๆข