diff --git a/practical_exercises/key_exercises/输入输出运算符重载.cpp b/practical_exercises/key_exercises/输入输出运算符重载.cpp
index e44834d..140b1c9 100644
--- a/practical_exercises/key_exercises/输入输出运算符重载.cpp
+++ b/practical_exercises/key_exercises/输入输出运算符重载.cpp
@@ -2,38 +2,48 @@
  ��һ������Ա��Sales�������ݳ�Ա������name������֤��id������age��
  ��������/��������ʵ�ֶ�Sales�����ݳ�Ա������������
 */
-#include<iostream.h>
-#include<string.h>
-class Sales{
-private:
-		char name[10];
-		char id[18];
-		int age;
-public:
-		Sales(char *Name,char *ID,int Age);
+#include <iostream>
+#include <cstring>
+using namespace std;
 
-		friend	Sales &operator<<(ostream &os,Sales &s);	//������������
-		friend	Sales &operator>>(istream &is,Sales &s);	//�������������
+class Sales
+{
+private:
+    char name[10];
+    char id[18];
+    int age;
+
+public:
+    Sales(char *Name, char *ID, int Age);
+
+    friend Sales &operator<<(ostream &os, Sales &s); //������������
+    friend Sales &operator>>(istream &is, Sales &s); //�������������
 };
-Sales::Sales(char *Name,char *ID,int Age) {
-		strcpy(name,Name);
-		strcpy(id,ID);
-		age=Age;
+Sales::Sales(char *Name, char *ID, int Age)
+{
+    strcpy(name, Name);
+    strcpy(id, ID);
+    age = Age;
 }
-Sales& operator<<(ostream &os,Sales &s) {
-		os<<s.name<<"\t";                 			//�������
-		os<<s.id<<"\t";                    			//�������֤��
-		os<<s.age<<endl;                  			//�������
-		return s;
+Sales &operator<<(ostream &os, Sales &s)
+{
+    os << s.name << "\t"; //�������
+    os << s.id << "\t";	  //�������֤��
+    os << s.age << endl;  //�������
+    return s;
 }
-Sales &operator>>(istream &is,Sales &s) {
-		cout<<"�����Ա������������֤�ţ�����"<<endl;  				is>>s.name>>s.id>>s.age;                       	
-		return s;
+Sales &operator>>(istream &is, Sales &s)
+{
+    cout << "�����Ա������������֤�ţ�����" << endl;
+    is >> s.name >> s.id >> s.age;
+    return s;
 }
-void main(){
-		Sales s1("�ſ�","214198012111711",40);   		//L1
-		cout<<s1;                             			//L2
-		cout<<endl;                           				//L3
-		cin>>s1;                              				//L4
-		cout<<s1;                             				//L5
+int main()
+{
+    Sales s1("�ſ�", "214198012111711", 40); //L1
+    cout << s1;								 //L2
+    cout << endl;							 //L3
+    cin >> s1;								 //L4
+    cout << s1;								 //L5
+    return 0;
 }