Else's blog

輸入A,R,N數值後, Click 試算可計算 P1,P2,P3 值, Check A,N 應為整數

r=R/12, n=12*N
P1=Q1+I1    Q1=A/n    I1=A*r    A1=A-Q1
P2=Q2+I2    Q2=A/n    I2=A1*r    A2=A1-Q2
P3=Q3+I3    Q3=A/n    I3=A2*r    A3=A2-Q3

Q1,Q2,Q3都等於A/n所以設Q=A/n

r=R/12, n=12*N
開始變化的月份設n
P1=Q+I1    Q=A/n    I1=A*r    A1=A-Q
P2=Q+I2    Q=A/n    I2=A1*r    A2=A1-Q
P3=Q+I3    Q=A/n    I3=A2*r    A3=A2-Q
Ax=A-Q*x
Ix = (A-Q*(x-1))*r
Px=Q+(A-Q*(x-1))*r
Px=A/n+(A-(A/n)*(x-1))*r
x是月份,

       public string principalInterest(string _amount, string _interest_ratels, string _year,int _month)
       {
            //r=R/12, n=12*N
            //P1=Q1+I1    Q1=A/n    I1=A*r    A1=A-Q1
            //P2=Q2+I2    Q2=A/n    I2=A1*r    A2=A1-Q2
            //P3=Q3+I3    Q3=A/n    I3=A2*r    A3=A2-Q3

           //轉換類型，使之在form裡面不用轉換
           double amount = Convert.ToDouble(_amount);
           double interest_ratels = Convert.ToDouble(_interest_ratels);
           double year = Convert.ToDouble(_year);

           double n = year * 12;               //算總的月份
           double r = interest_ratels / 12 / 100;  //每個月
           double A = amount * 10000;         //amount傳進來的單位是萬

           double P,x;
           int month = _month;
           x=month;
           //推出算公式
           //Px=Q+(A-Q*(x-1))*r　其中x表是第x月份
           //Px=A/n+(A-(A/n)*(x-1))*r Px就是第幾月分要還回的值
          

          
           if (amount != 0 && year != 0 && interest_ratels != 0 && month!=0)
           {
               P = A/n+(A-(A/n)*(x-1))*r;
               return P.ToString("#");
           }

           else
           {
               return "0";
           }

       }