EX 9

优于别人，并不高贵，真正的高贵，应该是优于过去的自己。

　　　　　　　　　　　　　　　　　　　　　　　　　　—— 海明威 《真实的高贵》

ps：算是手速场吧，没有像上场那么自闭，看来喊喊rank1还是有用的，嘻嘻。

Problem A: 第一个类

main函数：

int main()
{
    Thing A("Car");
    string str;
    cin>>str;
    Thing B(str);
    return 0;
}

水。。。。。。。。

AC代码：

#include <bits/stdc++.h>
using namespace std;
struct Thing
{
    string name;
public:
    Thing(string _name):name(_name){cout << "Construct a thing " << name << endl; }
    ~Thing()
{
    cout << "Destroy a thing " << name << endl;
}
};

Problem B: 建造一间教室

main函数：

int main()
{
    int nl, nc;
    int w;
    string color;
    cin>>w>>color;
    Light light(w);
    Chair chair(color);
    cin>>nl>>nc;
    cin>>w>>color;
    ClassRoom room(nl, nc, w, color);
    return 0;
}

半水吧，就一个坑点，chair类的析构也输出created，还好测了遍样例，手动狗头。

AC代码：

#include <bits/stdc++.h>
using namespace std;
class Light
{
    int w;
public:
    Light(int _w):w(_w)
    {
        printf("A %dw light is created.
",w);
    }
    ~Light()
    {
         printf("A %dw light is erased.
",w);
    }
};
class Chair
{
    string co;
public:
    Chair(string _co):co(_co)
    {
        cout << "A " << co << " chair is created." << endl;
    }
    ~Chair()
    {
        cout << "A " << co << " chair is created." << endl;
    }
};
class ClassRoom
{
 
    Light li;Chair ch;
    int n_c;
    int n_l;
public:
    ClassRoom(int _c,int _l,int _li,string _ch):n_c(_c),n_l(_l),li(_li),ch(_ch)
    {
        printf("A classroom having %d lights and %d chairs is created.
",n_c,n_l);
    }
    ~ClassRoom()
    {
         printf("A classroom having %d lights and %d chairs is erased.
",n_c,n_l);
    }
};

Problem C: 是否回文数？

main函数：

int main()
{
    Data data;
    int v;
    while (cin>>v)
    {
        data.setValue(v);
        if (data.isPalindrome())
            cout<<"Yes"<<endl;
        else
            cout<<"No"<<endl;
    }
    return 0;
}

重点应该是在isPalindrome函数的设计的吧，基本思路应该是先取个abs，然后转化为字符串看是否对称的吧。

way1 : 使用sprintf 函数将数字转化为字符串 sprintf(要转入的字符数组s，格式控制符，转出的数字)；

way2: 使用STL库中的反转函数 reverse(s.begin()，s.end())；

ac代码：

#include <bits/stdc++.h>
using namespace std;
class Data
{
    int v;
public:

    Data(){}
    void setValue(int x){v =x;}
    bool isPalindrome()// way 1
    {
        int d = v;
        d = abs(d);
        char s[20];
        sprintf(s,"%d",d);
        int len = strlen(s);
        for(int i = 0,j=len-1;i<=j;i++,j--)
            if(s[i]!=s[j])
                return false;
        return true;
    }
bool isPalindrome()// way 2
{
    int d = abs(v);
    string s,s1;
    while(d)
    {
        s+=(d%10+'0');
        d/=10;
    }
    s1 = s;
    int len = s.size();
    reverse(s1.begin(),s1.end());
    for(int i = 0;i<=(len+1)/2;i++)
        if(s[i]!=s1[i])
            return false;
    return true;
}
};

Problem D: Base与Derived

main函数：

int main()
{
    int a, b;
    cin>>a>>b;
    Base base(a);
    Derived derived(a, b);
    return 0;
}

 水，细节题，析构输出created 。。。。

AC代码：

#include <bits/stdc++.h>
using namespace std;
class Base
{
    int b;
public:
    Base(int _b):b(_b)
    {
        printf("Base %d is created.
",b);
    }
    ~Base()
    {
         printf("Base %d is created.
",b);
    }
};
class Derived:public Base
{
    int d;
public:
    Derived(int _b,int _d):Base(_b),d(_d)
    {
        printf("Derived %d is created.
",d);
    };
    ~Derived ()
    {
        printf("Derived %d is created.
",d);
    }
};

Problem E: 类模板Sample

main函数：

int main()
{
    int a, b;
    double c, d;
    cin>>a>>b>>c>>d;
    Sample<int> s1(a), s2(b), s3(s1);
    Sample<double> s4(c), s5(d), s6(s5);
    s1.add(s2);
    s1.show();
    s5.add(s4);
    s5.show();
    return 0;
}

类模板

AC代码：

#include <bits/stdc++.h>
using namespace std;
template <class T>
class Sample
{
T num;
public:
Sample(T _num):num(_num)
{
cout << "Sample " << num << " is created." << endl;
}
template <class T1>
Sample(Sample<T1> &b)
{
num = b.num;
cout << "Sample " << num << " is copied." << endl;
}
void show()
{
cout << num << endl;
}
template <class T1>
void add(Sample<T1> b)
{
num+=b.num;
}
};