const成员函数修改成员变量

#include <iostream>
#include <iomanip>

using namespace std;

class klass
{
public:
    klass(int i):m_Count(i){};
    int incr()const {
        return ++m_Count;
    }
    int decr()const {
        return --m_Count;
    }
private:
    mutable int m_Count;
};

int
main(void)
{
    klass k1(0), k2(10);
    int tmp, i;
    for (i = 0; i < 10; i++)
    {
        tmp = k1.incr();
        cout << setw(tmp)<<setfill(' ')<<tmp<<endl;
        tmp = k2.decr();
        cout << setw(tmp)<<setfill(' ')<<tmp<<endl;
    }

    return (0);
}