新增模块

rust_project/src/main.rs

@@ -1,3 +1,8 @@
+mod second;
+use second::ClassName;
+
 fn main() {
+    let object = ClassName::new(1024);
+    object.public_method();
     println!("Hello, world!");
 }

rust_project/src/second.rs

@@ -0,0 +1,20 @@
+pub struct ClassName {
+    field: i32,
+}
+
+impl ClassName {
+    pub fn new(value: i32) -> ClassName {
+        ClassName {
+            field: value
+        }
+    }
+
+    pub fn public_method(&self) {
+        println!("from public method");
+        self.private_method();
+    }
+
+    fn private_method(&self) {
+        println!("from private method");
+    }
+}