用职责链模式来实现计算器

 

四则运算式解释,并计算

语法分析

 

using System;
using System.Collections;

namespace myChain
...{
    /**//// <summary>
    /// 自定义的CxyStack。
    /// </summary>
    public class cxyStack
    ...{
        private Stack mystack;
        public cxyStack()
        ...{ 
            mystack=new Stack();
        }

        public void Push(object o)
        ...{
            mystack.Push(o);
        }

        public object Pop()
        ...{
            return mystack.Pop();
        }

        public bool IsEmpty()
        ...{
            return mystack.Count==0;
        }

        public int Count
        ...{
            get...{return mystack.Count;}
        }

        public object TopItem()
        ...{
            return mystack.Peek();
        }
    }


    /**//// <summary>
    /// 处理四则表达式中Token的基础类
    /// </summary>
    public abstract class TreateToken
    ...{
        //用来处理Token的临时堆栈
        protected cxyStack st;
        //用来保存结果的堆栈
        protected cxyStack stOutput;
        //Next构成职责链
        protected TreateToken next;

        public TreateToken Next
        ...{
            get...{return next;}
            set...{next=value;}
        }

        public TreateToken(cxyStack tst,cxyStack tstOut)
        ...{
            this.st=tst;
            this.stOutput=tstOut;
        }

        public abstract void Treat(string s);

    }

    /**//// <summary>
    /// 处理数字
    /// </summary>
    public class NumberToToken:TreateToken
    ...{
        public NumberToToken(cxyStack tst,cxyStack tstOut):base(tst,tstOut)
        ...{

        }

        public override void Treat(string s)
        ...{
            if(Char.IsNumber(s,0))
            ...{
                stOutput.Push(s);
            }
            else
            ...{
                next.Treat(s);
            }
        } 
    }

    /**//// <summary>
    /// 处理字符串+-*/()
    /// </summary>
    public class OperatorToken:TreateToken
    ...{
        private myOperator ope;

        public OperatorToken(cxyStack tst,cxyStack tstOut,myOperator op):base(tst,tstOut)
        ...{
            this.ope=op;
        }

        public override void Treat(string s)
        ...{
            if(s==ope.Op)
            ...{
                if(st.IsEmpty()||s=="(")
                ...{
                    st.Push(ope);
                }
                else
                ...{
                    myOperator o=(myOperator) st.TopItem();
                    while(o.Level>=ope.Level||ope.Op==")")
                    ...{
                        myOperator ol=(myOperator)st.Pop();
                        if(ol.Op=="(") break;

                        this.stOutput.Push(ol);
                        if(st.IsEmpty()) break;
                        o=(myOperator)st.TopItem();
                    }
                    if(ope.Op!=")")
                        st.Push(ope);
                }
            }
            else
                next.Treat(s);
        }

    }

    /**//// <summary>
    /// 操作符与优先级
    /// </summary>
    public class myOperator
    ...{
        private string ope;
        private int level;

        public myOperator(string o,int l)
        ...{
            ope=o;level=l;
        }

        public string Op
        ...{
            get...{return ope;}
            set...{ope=value;}
        }

        public int Level
        ...{
            get...{return level;}             
        }

        public override string ToString()
        ...{
            return ope;
        }

    }

    /**//// <summary>
    /// 处理除字符串和操作符之外的字符
    /// </summary>
    public class OtherToken:TreateToken
    ...{
        public OtherToken():base(null,null)
        ...{
        }

        public override void Treat(string s)
        ...{
            if(s!="")
                throw new ArgumentException("无法识别的操作符"+s);
        } 
    }






}

 

计算机

 

using System;
using System.Collections;

namespace myChain
...{ 
    public abstract class CompToken:TreateToken
    ...{
        protected string token=" ";
        public CompToken(cxyStack sstemp,cxyStack soutput):base(sstemp,soutput)
        ...{

        }
        public override void Treat(string s)
        ...{
            if(s==token) ...{
                double b=Convert.ToDouble(stOutput.Pop().ToString());
                double a=Convert.ToDouble(stOutput.Pop().ToString());
                double c=Comp(a,b);
                this.stOutput.Push(c.ToString());
            }
            else ...{
                this.next.Treat(s);
            }
        }
 

        public abstract double Comp(double a,double b);

    }


    public class AddToken:CompToken 
    ...{

        public AddToken(cxyStack sstemp,cxyStack stout):base(sstemp,stout) 
        ...{
            token="+";

        }

        public override double Comp(double a, double b)
        ...{
            return a+b;
        } 

    }

    public class MinusToken:CompToken
    ...{
        public MinusToken(cxyStack sstemp,cxyStack stout):base(sstemp,stout)
        ...{
            token="-";
        }

        public override double Comp(double a, double b)
        ...{
            return a-b;
        }

    }

    public class ByToken:CompToken
    ...{
        public ByToken(cxyStack sstemp,cxyStack stout):base(sstemp,stout)
        ...{
            token="*";
        }

        public override double Comp(double a, double b)
        ...{
            return a*b;
        }

    }

    public class DivideToken:CompToken
    ...{
        public DivideToken(cxyStack sstemp,cxyStack stout):base(sstemp,stout)
        ...{
            token="/"; 
        }

        public override double Comp(double a, double b)
        ...{
            return a/b;
        }

    }

    public class ChangFange:CompToken
    ...{
        public ChangFange(cxyStack sstemp,cxyStack stout):base(sstemp,stout)
        ...{
            token="^";
        }

        public override double Comp(double a, double b)
        ...{
            return Math.Pow(a,b);
        }


    }

    public class Computer
    ...{
        private cxyStack InStack;
        private cxyStack OutStack=new cxyStack();

        private TreateToken tk;

        public Computer(cxyStack inStk)
        ...{
            InStack=inStk;

            tk=new NumberToToken(InStack,OutStack); 

            ArrayList configFile=new ArrayList();
            MyConstruct addcon=new MyConstruct();
            addcon.TypeStr= "myChain.AddToken";

            MyConstruct minuscon=new MyConstruct();
            minuscon.TypeStr="myChain.MinusToken";
            

            MyConstruct bycon=new MyConstruct();
            bycon.TypeStr="myChain.ByToken";

            MyConstruct divecon=new MyConstruct();
            divecon.TypeStr="myChain.DivideToken";

            MyConstruct changfange=new MyConstruct();
            changfange.TypeStr="myChain.ChangFange";

            configFile.Add(addcon);
            configFile.Add(minuscon);
            configFile.Add(bycon);
            configFile.Add(divecon);
            configFile.Add(changfange);
            

            ArrayList comar=ComputChainFactory.GetChain(InStack,OutStack,configFile);

            tk.Next=(CompToken)comar[0];


        }

        public string Do()
        ...{
            while(InStack.Count>0)
            ...{
                string s=InStack.Pop().ToString();
                tk.Treat(s);
            }
            return OutStack.Pop().ToString();
        }
    }



}