C2662 不能将"this"指针从const xxx" 转换为"xxx &"

C2662 不能将"this"指针从const student" 转换为"student &"

运行环境:
vc2010学习版

例子:

#include <iostream>
#include <set>
#include <functional>
#include <algorithm>

using namespace std;

class student
{
public:
	student(int age)
	{
		this->age = age;
	}

	bool operator < (const student &right) const
	{
		return this->age < right.age;
	}

	int getAge()
	{
		return age;
	}

private:
	int age;
};

int main()
{
	set<student> setStu; //等同于 set<student, less<student>>
	setStu.insert(student(18));
	setStu.insert(student(19));

	for(set<student>::iterator it = setStu.begin(); it != setStu.end(); it++)
	{
		cout<<it->getAge();
		cout<<" ";
	}
	cout<<endl;

	system("pause");
	return 0;
}

报错如下:
error C2662: “student::getAge”: 不能将“this”指针从“const student”转换为“student &”

原因:
it 它是const 而 getAge 不是const, 因为 it 是常量一但涉及可能改变就会报错

解决方案:
修改:

int getAge() const
	{
		return age;
	}

运行结果:
18 19