From 90be696c185cee6045d18c9ef3da0548e87870df Mon Sep 17 00:00:00 2001
From: luming <lu.lm@bitsun-inc.com>
Date: Tue, 29 Jun 2021 13:51:16 +0800
Subject: [PATCH] =?UTF-8?q?=E9=9D=9E=E7=A9=BA=E8=B0=83=E7=94=A8?=
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---
 src/basic/Variable.kt | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/basic/Variable.kt b/src/basic/Variable.kt
index 9ff175a..091c087 100644
--- a/src/basic/Variable.kt
+++ b/src/basic/Variable.kt
@@ -99,4 +99,13 @@ fun main() {
         it == 6L
     }
     println(index)
+
+    // 可空变量
+    var str: String? = null
+    // 安全调用符
+    println(str?.length)
+    // 默认值
+    println(str?.length ?: "默认值")
+    // 非空断言 为空 运行时抛空指针异常
+    println(str!!.length)
 }
\ No newline at end of file