update lesson8

Author: jincheng9

workspace/lesson8/func.go

@@ -5,9 +5,31 @@ func add(a, b int, c, d string) (int, string) {
 	return a+b, c+d
 }
 
+func swap(a int, b int) {
+	println("[func|swap]a=", a, "b=", b)
+	a, b = b, a
+	println("[func|swap]a=", a, "b=", b)
+}
+
+func swapRef(pa *int, pb *int) {
+	println("[func|swapRef]a=", *pa, "b=", *pb)
+	var temp = *pa
+	*pa = *pb
+	*pb = temp
+	println("[func|swapRef]a=", *pa, "b=", *pb)
+}
+
 func main() {
 	a, b := 1, 2
 	c, d := "c", "d"
 	res1, res2 := add(a, b, c, d)
 	println("res1=", res1, "res2=", res2)
+
+	println("[func|main]a=", a, "b=", b)
+	swap(a, b)
+	println("[func|main]a=", a, "b=", b)
+
+	println("[func|main]a=", a, "b=", b)
+	swapRef(&a, &b)
+	println("[func|main]a=", a, "b=", b)	
 }

workspace/lesson8/readme.md

@@ -61,8 +61,87 @@
 
 * 函数参数
 
-  * 值传递
-  * 引用传递：指针
+  * 值传递：和C++里的传值一样，参加下例里的swap
+
+    ```go
+    package main
+    
+    
+    func add(a, b int, c, d string) (int, string) {
+    	return a+b, c+d
+    }
+    
+    func swap(a int, b int) {
+    	println("[func|swap]a=", a, "b=", b)
+    	a, b = b, a
+    	println("[func|swap]a=", a, "b=", b)
+    }
+    
+    func swapRef(pa *int, pb *int) {
+    	println("[func|swapRef]a=", *pa, "b=", *pb)
+    	var temp = *pa
+    	*pa = *pb
+    	*pb = temp
+    	println("[func|swapRef]a=", *pa, "b=", *pb)
+    }
+    
+    func main() {
+    	a, b := 1, 2
+    	c, d := "c", "d"
+    	res1, res2 := add(a, b, c, d)
+    	println("res1=", res1, "res2=", res2)
+    
+    	println("[func|main]a=", a, "b=", b)
+    	swap(a, b)
+    	println("[func|main]a=", a, "b=", b)
+    
+    	println("[func|main]a=", a, "b=", b)
+    	swapRef(&a, &b)
+    	println("[func|main]a=", a, "b=", b)	
+    }
+    ```
+
+  * 引用传递：和 C++里的传指针一样，参见下例里的swapRef
+
+    ```go
+    package main
+    
+    
+    func add(a, b int, c, d string) (int, string) {
+    	return a+b, c+d
+    }
+    
+    func swap(a int, b int) {
+    	println("[func|swap]a=", a, "b=", b)
+    	a, b = b, a
+    	println("[func|swap]a=", a, "b=", b)
+    }
+    
+    func swapRef(pa *int, pb *int) {
+    	println("[func|swapRef]a=", *pa, "b=", *pb)
+    	var temp = *pa
+    	*pa = *pb
+    	*pb = temp
+    	println("[func|swapRef]a=", *pa, "b=", *pb)
+    }
+    
+    func main() {
+    	a, b := 1, 2
+    	c, d := "c", "d"
+    	res1, res2 := add(a, b, c, d)
+    	println("res1=", res1, "res2=", res2)
+    
+    	println("[func|main]a=", a, "b=", b)
+    	swap(a, b)
+    	println("[func|main]a=", a, "b=", b)
+    
+    	println("[func|main]a=", a, "b=", b)
+    	swapRef(&a, &b)
+    	println("[func|main]a=", a, "b=", b)	
+    }
+    ```
+
+    
 
 * 函数高级用法