diff --git a/practical_exercises/10_day_practice/day7/综合例题/重要.cpp b/practical_exercises/10_day_practice/day7/综合例题/重要.cpp
index 10ec7ed..a7e5e42 100644
--- a/practical_exercises/10_day_practice/day7/综合例题/重要.cpp
+++ b/practical_exercises/10_day_practice/day7/综合例题/重要.cpp
@@ -1,26 +1,37 @@
-//���һ���ַ�����String��ͨ�����������ʵ���ַ��������롢����Լ�+=��==��!=��<��>��>=��[ ]�����㡣
+//设计一个字符串类String，通过运算符重载实现字符串的输入、输出以及+=、==、!=、<、>、>=、[ ]等运算。
 #include <iostream>
 #include <cstring>
 using namespace std;
 class String {
 private:
-int length;                     		//�ַ�������
-char *sPtr;                     		//����ַ�����ָ��
+int length;                     		//字符串长度
+char *sPtr;                     		//存放字符串的指针
 void setString( const char *s2);	
-friend ostream &operator<<(ostream &os, const String &s); 
-friend istream &operator>>(istream &is, String &s);  //�������������
+friend ostream &operator<<(ostream &os, const String &s)    
+{
+        return os << s.sPtr;
+}; 
+friend istream &operator>>(istream &is, String &s)
+{
+    return is >> s;
+};                                                 //重载输入运算符
 public:
     String( const char * = "" );                   
-    const String &operator=(const String &R); 		//���ظ�ֵ����� =
-    const String &operator+=(const String &R);		//�ַ��������� +=
-    bool operator==(const String &R);				//�ַ�������ȱȽ� ==
-    bool operator!=(const String &R);				//�ַ����IJ��ȱȽ� !=
-    bool operator!() ;               				//�ж��ַ����Ƿ�Ϊ��
-    bool operator<(const String &R) const;     		//�ַ�����С�ڱȽ� <
-    bool operator>(const String &R);                	//�ַ����Ĵ��ڱȽ� >
-    bool operator>=(const String &R);             	//�ַ����Ĵ��ڵ��ڱȽ�
-    char &operator[](int);                         	//�ַ������±�����
-    ~String();  
+    const String &operator=(const String &R)
+    {
+        length = R.length;
+        strcpy(R.sPtr, sPtr);
+        return *this;
+    } ; 		                                     //重载赋值运算符 =
+    const String &operator+=(const String &R);		//字符串的连接 +=
+    bool operator==(const String &R);				//字符串的相等比较 ==
+    bool operator!=(const String &R);				//字符串的不等比较 !=
+    bool operator!() ;               				//判定字符串是否为空
+    bool operator<(const String &R) const;     		//字符串的小于比较 <
+    bool operator>(const String &R);                	//字符串的大于比较 >
+    bool operator>=(const String &R);             	//字符串的大于等于比较
+    char &operator[](int);                         	//字符串的下标运算
+    ~String(){};  
 };
 const String &String::operator+=(const String &R) {
     char *temp = sPtr;              
@@ -31,6 +42,12 @@ const String &String::operator+=(const String &R) {
     delete [] temp;                 
     return *this;                         
 }
+String::String(const char *str)
+{
+    sPtr = new char[strlen(str) + 1];
+    strcpy(sPtr, str);
+    length = strlen(str);
+};
 bool String::operator==(const String &R){return strcmp(sPtr,R.sPtr)==0;}
 bool String::operator!=(const String & R){return !(*this==R);}
 bool String::operator!(){return length ==0;}
@@ -41,24 +58,24 @@ char &String::operator[](int subscript){return sPtr[subscript];}
 int main(){
     String s1("happy"),s2("new year"),s3;
     cout << "s1 is " << s1 << "\ns2 is " << s2 << "\ns3 is " << s3       
-    << "\n�Ƚ�s2��s1:"
-    << "\ns2 ==s1����� " << ( s2 == s1 ? "true" : "false")
-    << "\ns2 != s1����� " << ( s2 != s1 ? "true" : "false")
-    << "\ns2 >  s1����� " << ( s2 >  s1 ? "true" : "false") 
-    << "\ns2 <  s1����� " << ( s2 <  s1 ? "true" : "false") 
-    << "\ns2 >= s1����� " << ( s2 >= s1 ? "true" : "false");
-    cout << "\n\n����s3�Ƿ�Ϊ��: ";                         	
+    << "\n比较s2和s1:"
+    << "\ns2 ==s1结果是 " << ( s2 == s1 ? "true" : "false")
+    << "\ns2 != s1结果是 " << ( s2 != s1 ? "true" : "false")
+    << "\ns2 >  s1结果是 " << ( s2 >  s1 ? "true" : "false") 
+    << "\ns2 <  s1结果是 " << ( s2 <  s1 ? "true" : "false") 
+    << "\ns2 >= s1结果是 " << ( s2 >= s1 ? "true" : "false");
+    cout << "\n\n测试s3是否为空: ";                         	
     if (!s3){
-        cout << "s3�ǿմ�"<<endl;                           	//L3
-        cout<<"��s1����s3�Ľ���ǣ�";                    		       	
+        cout << "s3是空串"<<endl;                           	//L3
+        cout<<"把s1赋给s3的结果是：";                    		       	
         s3 = s1;                                         
         cout << "s3=" << s3 << "\n";                          	//L5
     }
-    cout << "s1 += s2 �Ľ���ǣ�s1=";                      	//L6
+    cout << "s1 += s2 的结果是：s1=";                      	//L6
     s1 += s2;                                       
     cout << s1;                                             		//L7
                                                         
-    cout << "\ns1 +=  to you �Ľ���ǣ�";                     	//L8
+    cout << "\ns1 +=  to you 的结果是：";                     	//L8
     s1 += " to you";                               
     cout << "s1 = " << s1 <<endl;                              	//L9
     s1[0] = 'H';