test: 更新 Demo20

playground/Demo/Demo20/Main.snow

@@ -1,11 +1,12 @@
 module: Main
     import:os
     function: main
-        return_type: double
+        return_type: void
         body:
-            declare n: double[] = [10.0]
+            declare arr: int[] = [1, 2, 3]
+            arr[0] = 5
 
-            return n[0] + 1.0
+            os.print(arr[0])
         end body
     end function
 end module

playground/Demo/Demo20/OS.snow

@@ -0,0 +1,11 @@
+module: os
+    import: os
+    function: print
+        parameter:
+            declare i1: int
+        return_type: void
+        body:
+            syscall("PRINT",i1)
+        end body
+    end function
+end module