diff --git a/work20220407/string/String.cpp b/work20220407/string/String.cpp
index 1453bc8..402c027 100644
--- a/work20220407/string/String.cpp
+++ b/work20220407/string/String.cpp
@@ -15,9 +15,9 @@ String::String(int size) : length(0), allocSize(size) {
 }
 
 /**
- * 不设定初始化大小就默认64个字符来初始化
+ * 不设定初始化大小就默认128个字符来初始化
  */
-String::String() : String(64) {}
+String::String() : String(128) {}
 
 /**
  * 从源中复制字符串来构建新的对象
@@ -160,18 +160,17 @@ void String::addString(const char *source, int sourceLength) {
         char *old = new char[length + 1]();
         strcpy(old, data);
 
-        // 重新分配内存，防止拼接后溢出，2为两个横杠大小
-        length += sourceLength;
-        allocSize = length + 1;
 
+        // 重新分配内存，防止拼接后溢出
         delete[] data;
+        allocSize = length + sourceLength + 1;
         this->data = new char[allocSize]();
 
         strcpy(data, old);
     }
 
     strcat(data, source);
-    length += sourceLength;
+    length = allocSize - 1;
 }
 
 /**