类外定义

文件内类外定义，类的定义和声明全部写在一个文件里面：

#include <iostream>
#include <string>
using namespace std;

class teacher{
  public:
  void setName(string _name);
  string getName();
  void setGender(string _gender);
  string getGender();
  void teach();
  
  private:
  string strName;
  string strGender;
};
 void teacher::setName(string _name){
      strName=_name;
  }
  string teacher::getName(){
      return strName;
  }
  void teacher::setGender(string _gender){
      strGender=_gender;
  }
  string teacher::getGender(){
      return strGender;
  }
  void teacher::teach(){
      cout << "上课" << endl;
  }


int main()
{
    teacher t;
    t.setName("A");
    t.setGender("女");
    cout << t.getName() + "  " << t.getGender() << endl;
    t.teach();
    return 0;
}
 

文件外类外定义，将类分成两个文件定义，一个用来声明（.h文件），另一个用来写函数体（.cpp文件）：

定义一个头文件：Teacher.h

#pragma once
#include <iostream>
#include <string>
using namespace std;

class Teacher {
public:
Teacher(string _name="aaa", string _gender="男"); // 构造函数
void setName(string _name);
string getName();
void setGender(string _gender);
string getGender();
void teach();

private:
string strName;
string strGender;
};

再把函数体写到一个cpp文件里面，Teacher.cpp：

#include <iostream>
#include <string>
#include <stdlib.h>
#include "Teacher.h"
#include "stdafx.h"
using namespace std;

Teacher::Teacher(string _name, string _gender):strName(_name),strGender(_gender) {

} // 初始化列表先于构造函数之前被加载，而且初始化列表可以对const变量赋值
void Teacher::setName(string _name) {
strName = _name;
}
string Teacher::getName() {
return strName;
}
void Teacher::setGender(string _gender) {
strGender = _gender;
}
string Teacher::getGender() {
return strGender;
}
void Teacher::teach() {
cout << "上课" << endl;
}

主程序：

// ConsoleApplication3.cpp: 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <stdlib.h>
#include <iostream>
#include <string>
#include "Teacher.h"
using namespace std;

int main()
{
Teacher t;
cout << t.getName() + " " << t.getGender();
t.teach();
Teacher t1("Tom","男");
cout << t1.getName() + " " << t1.getGender();
t1.teach();
system("pause");
return 0;
}