add lib crate to chapter2 & chapter3

Author: yuk1ty

Cargo.lock

@@ -17,5 +17,6 @@ members = [
     "chapter15",
     "chapter16",
     "chapter17",
-    "appendix"
+    "appendix",
+    "lib"
 ]

Cargo.toml

@@ -7,6 +7,7 @@ version = "0.1.0"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+lib = { "../lib" }
 
 [[bin]]
 name = "2_4_1"

chapter2/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+lib = { "../lib" }
 
 [[bin]]
 name = "main_3_1"

chapter3/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "lib"
+version = "0.1.0"
+authors = ["yuk1ty <[email protected]>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

lib/Cargo.toml

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}