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.\n",w);}~Light(){printf("A %dw light is erased.\n",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",n_c,n_l);}~ClassRoom(){printf("A classroom having %d lights and %d chairs is erased.\n",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;elsecout<<"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.\n",b);}~Base(){printf("Base %d is created.\n",b);}
};
class Derived:public Base
{int d;
public:Derived(int _b,int _d):Base(_b),d(_d){printf("Derived %d is created.\n",d);};~Derived (){printf("Derived %d is created.\n",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;
}
};