C#实现的等额本息法、按月付息到期还本法、一次性还本付息法

void Main()

{

    var x = DengEBenXi.Compute(11111, 12, 3);

    x.Dump();

    var y = AnYueFuxiDaoqiHuanBen.Compute(11111, 12, 3);

    y.Dump();

    var z = YicixingHuanBenFuxi.Compute(11111, 12, 3);

    z.Dump();

}

    public class DengEBenXi

    {

        /// <summary>

        /// 等额本息法

        /// </summary>

        /// <param name="amountT">投资金额</param>

        /// <param name="yearRate">年利率</param>

        /// <param name="monthsx">投资期限，单位：月</param>

        /// <returns></returns>

        public static List<BackUnit> Compute(double amount, double yearRate, int months)

        {

            var monthRate = (yearRate) / 1200.0;     //年利率转为月利率

            var datalist = new List<BackUnit>();  

            var i = 0;

            var a = 0.0; // 偿还本息

            var b = 0.0; // 偿还利息

            var c = 0.0; // 偿还本金

            //利息收益

            var totalRateIncome =

                (amount * months * monthRate * Math.Pow((1 + monthRate), months)) / (Math.Pow((1 + monthRate), months) - 1) - amount;

            var totalIncome = totalRateIncome + amount;

            var d = amount + totalRateIncome; // 剩余本金

            totalRateIncome = Math.Round(totalRateIncome * 100) / 100;// 支付总利息

            totalIncome = Math.Round(totalIncome * 100) / 100;

            a = totalIncome / months;    //每月还款本息

            a = Math.Round(a * 100) / 100;//每月还款本息

            for (i = 1; i <= months; i++)

            {

                b = (amount * monthRate * (Math.Pow((1 + monthRate), months) - Math.Pow((1 + monthRate), (i - 1)))) / (Math.Pow((1 + monthRate), months) - 1);

                b = Math.Round(b * 100) / 100;

                c = a - b;

                c = Math.Round(c * 100) / 100;

                d = d - a;

                d = Math.Round(d * 100) / 100;

                if (i == months)

                {

                    c = c + d;

                    b = b - d;

                    c = Math.Round(c * 100) / 100;

                    b = Math.Round(b * 100) / 100;

                    d = 0;

                }

                var unit = new BackUnit();

                unit.Number = i;// 期数

                unit.TotalRate = totalRateIncome;// 总利息

                unit.TotalMoney = totalIncome;// 总还款

                unit.A = a;// 偿还本息  someNumber.ToString("N2");

                unit.B = b;// 偿还利息

                unit.C = c;// 偿还本金

                unit.D = d;// 剩余本金

                datalist.Add(unit);

            }

            return datalist;

        }

    }

    public class AnYueFuxiDaoqiHuanBen

    {

        /// <summary>

        /// 按月付息到期还本

        /// </summary>

        /// <param name="amount">投资金额</param>

        /// <param name="yearRate">年利率</param>

        /// <param name="months">投资期限，单位：月</param>

        /// <returns></returns>

        public static List<BackUnit> Compute(double amount, double yearRate, int months)

        {

            var datalist = new List<BackUnit>();  //new Array(Deadline);     //

            double rateIncome = amount * yearRate / 100 * (months / 12.0);

            double rateIncomeEve = (rateIncome / months);

            var total = amount + rateIncome;

            for (var i = 1; i < months; i++)

            {

                var unit = new BackUnit();

                unit.Number = i;// 期数

                unit.TotalRate = rateIncome;//Math.Round((Amount + TotalRate) * 100) / 100;// 总利息

                unit.TotalMoney = total;//TotalRate;// 总还款

                unit.A = rateIncomeEve;// 偿还本息  someNumber.ToString("N2");

                unit.B = rateIncomeEve;// 偿还利息

                unit.C = 0;// 偿还本金

                unit.D = amount * 1 + rateIncome * 1 - rateIncomeEve * i;// 剩余本金

                datalist.Add(unit);

            }

            datalist.Add(new BackUnit() { 

                Number= months,

                TotalRate = rateIncome,

                TotalMoney = total,

                A = amount + rateIncomeEve,

                B = rateIncomeEve,

                C = amount,

                D = 0

            });

            return datalist;

        }

    }

    public class YicixingHuanBenFuxi

    {

        /// <summary>

        /// 一次性还本付息

        /// </summary>

        /// <param name="amount">投资金额</param>

        /// <param name="yearRate">年利率</param>

        /// <param name="months">投资期限，单位：月</param>

        /// <returns></returns>

        public static BackUnit Compute(double amount, double yearRate, int months)

        {

            BackUnit unit = new BackUnit();

            var rate = yearRate;

            var rateIncome = amount * rate / 100 * (months / 12.0);

            var totalIncome = amount + rateIncome;

            unit.Number = 1;// 期数

            unit.TotalRate = rateIncome;//Math.Round((Amount + TotalRate) * 100) / 100;// 总利息

            unit.TotalMoney = totalIncome;//TotalRate;// 总还款

            unit.A = totalIncome;// 偿还本息  someNumber.ToString("N2");

            unit.B = rateIncome;// 偿还利息

            unit.C = 0;// 偿还本金

            unit.D = 0;// 剩余本金 

            return unit;

        }

    }

    public class BackUnit

    {

        //当前期数

        public int Number { get; set; }

        //总利息

        public double TotalRate { get; set; }

        //总还款

        public double TotalMoney { get; set; }

        //本期应还全部

        public double A { get; set; }

        //本期应还利息

        public double B { get; set; }

        //本期应还本金

        public double C { get; set; }

        //本期剩余本金

        public double D { get; set; }

    }