设计模式——简单工厂
作者：互联网
第一版： 简单实现
在int main 主函数中读取数据，使用switch语句分别进行操作。不同操作用类实现。
#include <iostream>
using namespace std;
static int num_a;
static int num_b;
static char op;
void input_num()
{
cout<<"input_num : ";
}
void input_op()
{
cout<<"input_op : ";
}
class Op_Add
{
public:
int calc()
{
return num_a+num_b;
}
};
class Op_Minus
{
public:
int calc()
{
return num_a-num_b;
}
};
class Op_Mut
{
public:
int calc()
{
return num_a*num_b;
}
};
class Op_Div
{
public:
int calc()
{
if(num_b)
{
return num_a/num_b;
}
else
{
cout<<"分母为0"<<endl;
return 0;
}
}
};
int main(int argc, char *argv[])
{
input_num();
cin>>num_a;
input_num();
cin>>num_b;
input_op();
cin>>op;
switch (op)
{
case '+':
{
Op_Add op1;
cout<<"result is "<<op1.calc()<<endl;
break;
}
case '-':
{
Op_Minus op2;
cout<<"result is "<<op2.calc()<<endl;
break;
}
case '*':
{
Op_Mut op3;
cout<<"result is "<<op3.calc()<<endl;
break;
}
case '/':
{
Op_Div op4;
cout<<"result is "<<op4.calc()<<endl;
break;
}
default:
break;
}
return 0;
}
第二版：输入数据和计算结果分离
使用Input类输入数据，operation类实现计算。
int main主函数语句变少。
#include <iostream>
using namespace std;
//依据使用习惯，输入数字，再输入运算符
//使用静态变量存储要进行操作的数和符号
//Input类从终端读取数据
static int num_a=0;
static int num_b=0;
static char op;
class Input
{
public:
void input_num();
void input_op();
//static int num_a;
//static int num_b;
//char op;
istream& set_num_a(istream& is);
istream& set_num_b(istream& is);
istream& set_op(istream& is);
void read_data()
{
set_num_a(cin);
cout<<"input num_a"<<endl;
set_num_b(cin);
cout<<"input num_b"<<endl;
set_op(cin);
cout<<"input op"<<endl;
cout<<"input done"<<endl;
}
};
void Input::input_num()
{
cout<<"input_num : ";
}
void Input::input_op()
{
cout<<"input_op : ";
}
istream& Input::set_num_a(istream& is)
{
this->input_num();
is >> num_a;
//this->num_a = _a;
}
istream& Input::set_num_b(istream& is)
{
this->input_num();
is >> num_b;
//this->num_b = _b;
}
istream& Input::set_op(istream& is)
{
this->input_op();
is >> op;
//this->op = _op;
}
class Op_four //貌似没用的纯虚类
{
public:
virtual int calc()=0;
} ;
class Op_Add: public Op_four
{
public:
int calc()
{
cout<<"num_a "<<num_a<<endl;
cout<<"num_b "<<num_b<<endl;
return num_a+num_b;
}
};
class Op_Minus: public Op_four
{
public:
int calc()
{
return num_a-num_b;
}
};
class Op_Mut: public Op_four
{
public:
int calc()
{
return num_a*num_b;
}
};
class Op_Div: public Op_four
{
public:
int calc()
{
if(num_b)
{
return num_a/num_b;
}
else
{
cout<<"分母为0"<<endl;
return 0;
}
}
};
class Op_sqrt: public Op_four
{
public:
int calc()
{
if(num_a >=0 )
{
//开更号(假装完成)
cout<<"开更号"<<endl;
}
}
};
class Operation //运算类
{
public:
int get_result(int _a,int _b,char _op)
{
int result;
switch (_op)
{
case '+':
{
Op_Add op1;
cout<<"result is "<<op1.calc()<<endl;
break;
}
case '-':
{
Op_Minus op2;
cout<<"result is "<<op2.calc()<<endl;
break;
}
case '*':
{
Op_Mut op3;
cout<<"result is "<<op3.calc()<<endl;
break;
}
case '/':
{
Op_Div op4;
cout<<"result is "<<op4.calc()<<endl;
break;
}
case 's':
{
Op_sqrt op5;
cout<<"result is "<<op5.calc()<<endl;
}
default:
break;
}
}
};
int main(int argc, char *argv[])
{
Input input;
input.read_data();
Operation op1;
op1.get_result(num_a,num_b,op);
return 0;
}
第三版：
简单工厂模式：产品和工厂类。产品为抽象类，可以派生出不同的产品，工厂类中有switch语句可以进行判断。
#include <iostream>
using namespace std;
//先输入运算符，再输入数据
//定以四则运算的抽象类，作为父类，具有操作数字段
class Op_four// 抽象类
{
private:
int _num_a=0;
int _num_b=0;
public:
virtual int calc()=0;//重载函数
//获取运算符
int get_num_a()
{
return _num_a;
}
int get_num_b()
{
return _num_b;
}
//设置操作数
void set_num_a(istream& is)
{
cout<<"input_num : ";
is >> this->_num_a ;
}
void set_num_b(istream& is)
{
cout<<"input_num : ";
is >> this->_num_b ;
}
} ;
class Op_Add: public Op_four
{
public:
int calc()
{
//cout<<"num_a "<<num_a<<endl;
//cout<<"num_b "<<num_b<<endl;
return get_num_a()+get_num_b();
}
};
class Op_Minus: public Op_four
{
public:
int calc()
{
return get_num_a()- get_num_b();
}
};
class Op_Mut: public Op_four
{
public:
int calc()
{
return get_num_a()*get_num_b();
}
};
class Op_Div: public Op_four
{
public:
int calc()
{
if(get_num_b())
{
return get_num_a()/get_num_b();
}
else
{
cout<<"分母为0"<<endl;
return 0;
}
}
};
/*class Op_sqrt: public Op_four
{
public:
int calc()
{
if(num_a >=0 )
{
//开更号
cout<<"开更号"<<endl;
}
}
};*/
class OperationFactory //运算工厂类
{
public:
int get_result(char _op)
{
int result;
switch (_op)
{
case '+':
{
Op_Add op1;
op1.set_num_a(cin);
op1.set_num_b(cin);
cout<<"result is "<<op1.calc()<<endl;
break;
}
case '-':
{
Op_Minus op2;
op2.set_num_a(cin);
op2.set_num_b(cin);
cout<<"result is "<<op2.calc()<<endl;
break;
}
case '*':
{
Op_Mut op3;
op3.set_num_a(cin);
op3.set_num_b(cin);
cout<<"result is "<<op3.calc()<<endl;
break;
}
case '/':
{
Op_Div op4;
op4.set_num_a(cin);
op4.set_num_b(cin);
cout<<"result is "<<op4.calc()<<endl;
break;
}
/*case 's':
{
Op_sqrt op5;
cout<<"result is "<<op5.calc()<<endl;
}*/
default:
break;
}
}
};
int main(int argc, char *argv[])
{
OperationFactory *of=new OperationFactory();
//输入要进行的运算符号
of->get_result('-');
delete of;
return 0;
}
标签：set,int,工厂,num,static,istream,简单,设计模式,op 来源： https://www.cnblogs.com/pine-apple/p/16124135.html