课后习题编程题(C++语言程序设计 杨进才版)
第七章 类与对象
P241
//1.求三角形面积和周长
#include <iostream>
#include <cmath>
using namespace std;
class triangle
{
private:
double a,b,c;
public:
triangle(double a=0,double b=0,double c=0)
{
this->a=a;
this->b=b;
this->c=c;
}
double getarea()
{
double p=(a+b+c)/2.0;
return sqrt(p*(p-a)*(p-b)*(p-c));
}
double getcircum()
{
return a+b+c;
}
};
int main()
{
triangle t(1,1,1);
cout<<t.getarea()<<endl;
cout<<t.getcircum()<<endl;
return 0;
}
//2.定义point求距离
#include <iostream>
#include <cmath>
using namespace std;
class point
{
private:
double x,y;
public:
point(double x=0,double y=0)
{
this->x=x;
this->y=y;
}
double distance(point a)
{
return sqrt((x-a.x)*(x-a.x)+(y-a.y)*(y-a.y));
}
};
int main()
{
point p1;
point p2(1,1);
cout<<p1.distance(p2)<<endl;
return 0;
}
//3.定义日期类,求下一天
#include <iostream>
using namespace std;
bool is_leap(int n)
{
if(n%4==0)
{
if(n%100==0)
{
if(n%400==0)
return true;
return false;
}
return true;
}
return false;
}
class CData
{
private:
int y,m,d;
public:
CData(int y=0,int m=0,int d=0)
{
this->y=y;
this->m=m;
this->d=d;
}
void Newday()
{
if(m==12&&d==31)
{
y++;
m=1;
d=1;
return ;
}
if(is_leap(y))
{
if(m==2)
{
d++;
if(d==29)
d=1,m++;
else if(d>=30)
cout<<"input error!"<<endl;
return ;
}
}
else
{
if(m==2)
{
d++;
if(d==30)
d=1,m++;
return;
}
}
if(m==1||m==3||m==5||m==7||m==8||m==10||m==12)
{
if(d==31)
{
d=1;
m++;
}
else
d++;
}
else if(m==4||m==6||m==9||m==11)
{
if(d==30)
{
d=1;
m++;
}
else
d++;
}
}
void show()
{
cout<<y<<"."<<m<<"."<<d<<endl;
}
};
int main()
{
CData d(2012,2,28);
d.Newday();
d.show();
return 0;
}
//4.定义时钟类,模拟闹钟
//与北京时间同步,求勿鄙视
#include <iostream>
#include <time.h>
using namespace std;
class T
{
private:
int h,m,s,H,M,S;
public:
T(int h=0,int m=0,int s=0)
{
this->h=h;
this->s=s;
this->m=m;
}
T(long long tt)
{
s=tt%60;
tt/=60;
m=tt%60;
tt/=60;
h=tt%24;
h+=8;
h%=24;
}
void show()
{
cout<<h<<":"<<m<<":"<<s<<endl;
}
void set_alarm(int h=0,int m=0,int s=0)
{
this->H=h;
this->S=s;
this->M=m;
}
void fun()
{
long long r=time(0);
int ss=r%60;
r/=60;
int mm=r%60;
r/=60;
int hh=r%24;
hh+=8;
hh%=24;
if(hh!=h||ss!=s||mm!=m)
cout<<h<<":"<<m<<":"<<s<<endl;
h=hh;
m=mm;
s=ss;
}
bool is_ok()
{
if(h==H&&m==M&&s==S)
return true;
return false;
}
};
int main()
{
long long miao=time(0);
T c(miao);
c.set_alarm(10,32,00);
while(1)
{
if(c.is_ok())
{
c.show();
cout<<"\a\a\a\a\a\a\a\a\a\a\a\a\a\a\a\a\a\a\a\a"<<endl;
cout<<"pika~"<<endl;
break;
}
else
c.fun();
}
return 0;
}
//5.设计学生类,计算平均成绩
#include <iostream>
#include <cstring>
using namespace std;
class student
{
private:
long no;
char *name;
char *classname;
int grade;
static int num;
static int sum;
public:
student(long no=0,char *name=NULL,char *classname=NULL,int grade=0)
{
num++;
this->no=no;
this->name=new char [strlen(name)+1];
strcpy(this->name,name);
this->classname=new char [strlen(classname)+1];
strcpy(this->classname,classname);
this->grade=grade;
sum+=grade;
}
static double average()
{
return (sum*1.0/num);
}
};
int student::sum=0;
int student::num=0;
int main()
{
student s1(1234,"nimei","data",89);
student s2(1234,"nimei","data",90);
student s3(1234,"nimei","data",91);
student s4(1234,"nimei","data",92);
cout<<student::average()<<endl;
return 0;
}
//6.信息管理登陆系统
#include <iostream>
#include <cstring>
using namespace std;
class system
{
private:
char *name;
long long password;
public:
system(char *name=NULL,long long password=0)
{
this->password=password;
this->name=new char [strlen(name)+1];
strcpy(this->name,name);
}
bool is_ok(system &p)
{
if(password==p.password&&strcmp(p.name,name)==0)
return true;
return false;
}
};
int main()
{
system miao("nicai",1234);
int t=4;
while(t)
{
cout<<"please input the name :"<<endl;
char *name;
cin>>name;
cout<<"please input the password :"<<endl;
long long no;
cin>>no;
system wu(name,no);
if(wu.is_ok(miao))
{
cout<<"ok"<<endl;
break;
}
else
{
t--;
cout<<"wrong"<<endl<<endl;
if(t==0)
{
cout<<"sha bi !"<<endl;
cout<<"You are not allowed to loggin in"<<endl;
break;
}
cout<<"I will give you "<<t<<" more times"<<endl<<endl;
}
}
return 0;
}
//7.定义一个String类
//函数判断是否为子串,换成大写,转换成数
#include <iostream>
#include <cstring>
#include <cstdlib>
using namespace std;
class String
{
private:
char *str;
int len;
public:
String(const char *s)
{
str=new char[strlen(s)+1];
strcpy(str,s);
len=strlen(s);
}
int getlen()
{
return len;
}
bool issubstring(const String &sstr)
{
char *pstr=sstr.str;
int plen=sstr.len,j;
for(int i=0;i<len;i++)
{
int k=i;
for(j=0;j<plen;j++,k++)
if(pstr[j]!=str[i]) break;
if(j==plen) return true;
}
return false;
}
bool issubstring(const char *sstr)
{
int j;
for(int i=0;i<len;i++)
{
int k=i;
for(j=0;sstr[j];j++,k++)
if(sstr[j]!=str[k])
break;
if(!str[j]) return true;
}
return false;
}
long long strnum()
{
long long a;
a=atoi(str);
return a;
}
void touppercase()
{
for(int i=0;i<len;i++)
if(str[i]<='z'&&str[i]>='a')
str[i]-=32;
}
void show()
{
cout<<str<<" "<<len<<endl;
}
};
int main()
{
String s1("1234");
cout<<s1.strnum()<<endl;
String s2("abs");
s2.touppercase();
s2.show();
if(s2.issubstring("ABSFRE"))
cout<<"ok"<<endl;
else
cout<<"wrong"<<endl;
if(s2.issubstring(s1))
cout<<"ok"<<endl;
else
cout<<"wrong"<<endl;
return 0;
}
//8.集合类Set及操作
#include <iostream>
using namespace std;
class Set
{
private:
int n;
int *a;
public:
Set()
{
a=NULL;
n=0;
}
bool is_empty()
{
if(n)
return false;
return true;
}
int size()
{
return n;
}
bool is_in_set(int num)
{
for(int i=1;i<=n;i++)
if(a[i]==num)
return true;
return false;
}
bool is_in_set(int num)const
{
for(int i=1;i<=n;i++)
if(a[i]==num)
return true;
return false;
}
Set(Set &t)
{
this->n=t.n;
for(int i=1;i<=n;i++)
this->a[i]=t.a[i];
}
void insert(int num)
{
if(is_in_set(num))
return ;
int b[n];
for(int i=1;i<=n;i++)
b[i]=a[i];
delete []a;
n++;
a=new int [n+1];
for(int i=1;i<n;i++)
a[i]=b[i];
a[n]=num;
}
void show()
{
if(n==0)
{
cout<<"NULL"<<endl;
return;
}
cout<<"{ ";
for(int i=1;i<n;i++)
cout<<" "<<a[i]<<",";
cout<<" "<<a[n]<<" }"<<endl;
cout<<"size="<<n<<endl;
}
bool issubset(const Set &s) const
{
if(s.n>n) return false;
for(int i=1;i<=s.n;i++)
if(!is_in_set(s.a[i]))
return false;
return true;
}
bool is_equal(const Set &s) const
{
if(n!=s.n)
return false;
if(issubset(s))
return true;
return false;
}
Set Union(Set &s)
{
for(int i=1;i<=s.n;i++)
{
if(is_in_set(s.a[i]))
continue;
insert(s.a[i]);
}
return *this;
}
Set Intersection(Set &s)
{
Set A;
for(int i=1;i<=n;i++)
for(int j=1;j<=s.n;j++)
if(a[i]==s.a[j])
A.insert(a[i]);
return A;
}
Set difference(Set &s)
{
Set A;
for(int i=1;i<=n;i++)
if(!s.is_in_set(a[i]))
A.insert(a[i]);
return A;
}
};
int main()
{
Set s;
for(int i=1;i<=9;i++)
s.insert(i);
s.insert(1000);
s.show();
cout<<"Set s's size : "<<s.size()<<endl;
Set m;
for(int i=4;i<=8;i++)
m.insert(i);
m.insert(100);
m.show();
if(m.is_empty())
cout<<"empty."<<endl;
else
cout<<"not empty."<<endl;
if(s.issubset(m))
cout<<"Set s contains Set m."<<endl;
else
cout<<"Set s doesn't contains Set m."<<endl;
if(s.is_equal(m))
cout<<"equal."<<endl;
else
cout<<"different."<<endl;
s.Union(m);
s.show();
m.Intersection(s);
m.show();
s=s.difference(m);
s.show();
return 0;
}