diff --git a/Cargo.toml b/Cargo.toml
index c85444f..2c286c6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "qr"
-version = "0.1.1"
+version = "0.1.2"
 authors = ["Hatter Jiang <jht5945@gmail.com>"]
 edition = "2018"
 readme = "README.md"
diff --git a/README.md b/README.md
index f9e29b3..56a348f 100644
--- a/README.md
+++ b/README.md
@@ -1,11 +1,16 @@
 # qr
 
+QR cli tool
+
+Install:
 ```
-cargo install qr
+$ cargo install qr
+```
+
+Usage:
+```
+$ qr 'hello world'
 ```
 
 
-```
-qr 'hello world'
-```
 
diff --git a/src/main.rs b/src/main.rs
index 96fbb3a..467326c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,8 +1,11 @@
 use clap::{Arg, App};
 use qrcode::QrCode;
 
+const C_W: char = ' ';
+const C_B: char = '█';
 const W: &str = " ";
 const B: &str = " ";
+const NL: &str = "\n";
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let matches = App::new("QR cli")
@@ -24,7 +27,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let input_string = match input {
         Some(i) => i,
-        None => return Ok(()), // TODO
+        None => return Ok(()), // TODO no input
     };
 
     let code = QrCode::new(input_string.as_bytes()).unwrap();
@@ -35,31 +38,35 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     let mut output_stirng = String::with_capacity(1024);
     let mut ln_len = 0;
     for c in string.chars() {
-        if c == '█' || c == ' ' {
-            ln_len += 1;
-        } else {
-            break;
+        match c {
+            C_B | C_W => ln_len += 1,
+            _ => break,
         }
     }
-    for _ in 0..ln_len+2 {
+    println!("【QR test for: {}】", &input_string);
+    for _ in 0..ln_len+4 {
         output_stirng.push_str(W);
     }
-    output_stirng.push('\n');
+    output_stirng.push_str(NL);
+    output_stirng.push_str(W);
     output_stirng.push_str(W);
     for c in string.chars() {
-        if c == '█' {
-            output_stirng.push_str(B);
-        } else if c == ' ' {
-            output_stirng.push_str(W);
-        } else {
-            output_stirng.push_str(W);
-            output_stirng.push(c);
-            output_stirng.push_str(W);
+        match c {
+            C_B => output_stirng.push_str(B),
+            C_W => output_stirng.push_str(W),
+            _ => { // new line
+                output_stirng.push_str(W);
+                output_stirng.push_str(W);
+                output_stirng.push(c);
+                output_stirng.push_str(W);
+                output_stirng.push_str(W);
+            }
         }
     }
     output_stirng.push_str(W);
-    output_stirng.push('\n');
-    for _ in 0..ln_len+2 {
+    output_stirng.push_str(W);
+    output_stirng.push_str(NL);
+    for _ in 0..ln_len+4 {
         output_stirng.push_str(W);
     }
     println!("{}", output_stirng);