学习C++编程语言时接触到的几个知识点,分享给大家
## 组合
#include <iostream>
#include <string>
using namespace std;
class Date
{
private:
int year;
int month;
int day;
public:
Date(){} //默认构造
Date(int y,int m,int d) //带参构造
{
year=y;
month=m;
day=d;
}
void set() //设置数据函数
{
cin>>year>>month>>day;
}
void display() //显示函数
{
cout<<year<<"年"<<month<<"月"<<day<<"日";
}
};
class Person
{
private:
int num;
char sex;
Date birthday;
char ID[19];
public:
Person(){} //默认构造
Person(int n,int y,int m,int d,char id[19],char s='m'):birthday(y,m,d)
{
num=n;
sex=s;
strcpy(ID,id); //复制函数
} //有默认值的带参构造
Person(Person& p) //拷贝构造
{
num=p.num;
sex=p.sex;
birthday=p.birthday;
strcpy(ID,p.ID);
}
void input() //输入函数
{
cout<<"请输入相应数据:"<<endl;
cout<<"编号:";
cin>>num;
cout<<"性别(m/w m为男,w为女):";
cin>>sex;
cout<<"生日:";
birthday.set();
cout<<"身份证号:";
cin>>ID;
ID[18]='\0';
cout<<endl;
}
void output() //输出函数
{
cout<<"编号:"<<num<<endl;
cout<<"性别:"<<sex<<endl;
cout<<"生日:";
birthday.display();
cout<<endl;
cout<<"身份证号:"<<ID<<endl;
}
~Person(){} //析构函数
};
int main()
{
Person p1;
p1.input();
p1.output();
return 0;
}
## 友元函数
#include<iostream>
using namespace std;
class boat;
class car
{
private:
int weight;
public:
car (int j)
{weight=j;}
friend int getweight(car &c,boat &b);
friend int compare(car &c,boat &b);
int input()
{ cout<<"输入车的质量 :"<<endl;
cin>>weight; }
};
class boat
{
private:
int weight;
public:
boat (int i)
{weight=i;}
int input()
{ cout<<"输入船的质量 :"<<endl;
cin>>weight; }
friend int getweight(car &c,boat &b);
friend int compare(car &c,boat &b);
//比较
};
int getweight(car &c,boat &b)
{return c.weight+b.weight;}
int compare(car &c,boat &b)
{
if(c.weight>b.weight)
return c.weight;
else return b.weight;
}
int main()
{car c1(6);
boat b1(5);
c1.input();
b1.input();
cout<<"车与船的质量和为"<<getweight(c1,b1)<<"吨"<<endl;
cout<<"两者中最大质量为:"<<compare(c1,b1)<<"吨"<<endl;
return 0;
}
## 异常处理
#include<iostream>
using namespace std;
int devide(int x,int y)
{
if(y==0)
throw x;
return x/y;
}
int main()
{
try {
cout<<"8/2="<<devide(8,2)<<endl;
cout<<"5/0="<<devide(5,0)<<endl;
cout<<"6/2="<<devide(6,2)<<endl;
}
catch (int e)
{
cout<<e<<" is devided"<<endl;
}
cout<<"is ok"<<endl;
return 0;
}
// catch处理程序的出现次序很重要,因为在一个try 块中,异常处理程序是按照它的出现次序被检查的。只要找到一个异常类型,后面的异常处理都将被忽略。例如
//catch(…)可以捕获任何异常,因此在任何情况下其它catch子句都不会被检查,所以catch(…)应放在最后
## Operator重载
#include<iostream>
using namespace std;
class complex
{
float real;
float image;
public :
complex(){}
complex (float r,float i)
{real=r; image=i;}
complex operator + (complex p)
//运算符重载,其本身的功能不会丧失
{return complex(real+p.real,image+p.image);
}
complex operator - (complex &p)
{return complex(real-p.real,image-p.image);
}
complex operator * (complex &p)
{
complex c;
c.real=real*p.real-image*p.image;
c.image=image*p.real+real*p.image;
return c;
}
complex operator /(complex &p)
{
complex c;
int j;
j=p.real*p.real+p.image*p.image;
c.real=(real*p.real-(-1*image*p.image))/j;
c.image=(image*p.real+(-1*real*p.image))/j;
return c;
}/*complex operator / (complex &c2)
{
int j;
j=c2.real*c2.real+c2.image*c2.image;
return complex ((real*c2.real+image*c2.image)/j,(image*c2.real-real*c2.image)/j);
}*/
void display()
{
if(image>0)
{cout<<real<<"+";
cout<<image<<"i"<<endl;}
if(image<0)
{cout<<real;
cout<<image<<"i"<<endl;}
}
};
int main()
{
complex c1(5.0,2.0);
complex c2(3.0,-4.0);
complex c3;
cout<<"c1=";
c1.display();
cout<<endl;
cout<<"c2=";
c2.display();
cout<<endl;
c3=c1+c2;//c1 当前对象 c2参数
cout<<"c1+c2=";c3.display();
cout<<endl;
c3=c1-c2;
cout<<"c1-c2=";c3.display();
cout<<endl;
c3=c1*c2;
cout<<"c1*c2=";
c3.display();
cout<<endl;
c3=c1/c2;
//c3=c1.operator +(c2);//显式调用
cout<<"c1/c2=";
c3.display();
int a=3,b=5;
b=a+b;
//证明+本意
return 0;
}