diff --git a/inc/hgl/type/StrChar.h b/inc/hgl/type/StrChar.h
index 0eed054..29c6d7c 100644
--- a/inc/hgl/type/StrChar.h
+++ b/inc/hgl/type/StrChar.h
@@ -524,6 +524,7 @@ namespace hgl
      * @param str2 要查找的字符串
      * @param size2 str2的长度
      * @return str2在str1中所在位置的指针
+     * @return nullptr 没有找到
      */
     template<typename T1,typename T2>
     T1 *stristr(T1 *str1,const uint size1,T2 *str2,const uint size2)
@@ -568,7 +569,7 @@ namespace hgl
             ++cp;
         }
 
-        return(0);
+        return(nullptr);
     }
 
     /**
diff --git a/inc/hgl/type/String.h b/inc/hgl/type/String.h
index 9c3096c..eca7e90 100644
--- a/inc/hgl/type/String.h
+++ b/inc/hgl/type/String.h
@@ -153,6 +153,12 @@ namespace hgl
 
         #undef BASE_STRING_FLOAT_CONSTRUCT
 
+        template<typename N1,typename N2>
+        static String<T> percentOf(const N1 numerator,const N2 denominator,const uint frac_num)
+        {
+            return String<T>::floatOf(double(numerator)/double(denominator)*100.0f,frac_num);
+        }
+
         String(const int *value,int N)=delete;
 
         static String<T> numberOf(const int *value,int N)