第2回c#講習会演習の一部(サンプル)

Fraction.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication4
{
    class Fraction
    {
        #region プロパティ その1
        //private int _denominator;
        //public int Denominator
        //{
        //    get { return _denominator; }
        //    set { _denominator = value; }
        //}

        //private int _numerator;
        //public int Numerator
        //{
        //    get { return _numerator; }
        //    set { _numerator = value; }
        //}
        #endregion

        #region プロパティ その2-自動プロパティver.(推奨)
        public int Denominator
        {
            get;
            private set;
        }

        public int Numerator
        {
            get;
            private set;
        }
        #endregion

        public Fraction(int numerator, int denominator)
        {
            //if (denominator == 0) throw new Exception();

            Denominator = denominator;
            Numerator = numerator;
        }

        static public Fraction Create(int numerator, int denominator)
        {
            return new Fraction(numerator, denominator);
        }

        public void Show()
        {
            Console.WriteLine(Numerator + "/" + Denominator);
        }


        #region 四則演算 その1
        public Fraction Add(Fraction frac1, Fraction frac2)
        {
            int numerator1 = frac1.Numerator * frac2.Denominator;
            int numerator2 = frac2.Numerator * frac1.Denominator;
            int denominator = frac1.Denominator * frac2.Denominator;

            return new Fraction(numerator1 + numerator2, denominator);
        }

        public Fraction Subtract(Fraction frac1, Fraction frac2)
        {
            int denominator = frac1.Denominator * frac2.Denominator;
            int numerator1 = frac1.Numerator * frac2.Denominator;
            int numerator2 = frac2.Numerator * frac1.Denominator;

            return new Fraction(numerator1 - numerator2, denominator);
        }

        public Fraction Multiply(Fraction frac1, Fraction frac2)
        {
            return new Fraction(frac1.Numerator * frac2.Numerator, frac1.Denominator * frac2.Denominator);
        }

        public Fraction Divide(Fraction frac1, Fraction frac2)
        {
            //if (frac2.Numerator == 0) throw new DivideByZeroException();

            return new Fraction(frac1.Numerator * frac2.Denominator, frac1.Denominator * frac2.Numerator);
        }
        #endregion

        #region 四則演算 その2(推奨)
        public Fraction Add(Fraction frac)
        {
            int numerator1 = this.Numerator * frac.Denominator;
            int numerator2 = frac.Numerator * this.Denominator;
            int denominator = this.Denominator * frac.Denominator;

            return new Fraction(numerator1 + numerator2, denominator);
        }

        public Fraction Subtract(Fraction frac)
        {
            int denominator = this.Denominator * frac.Denominator;
            int numerator1 = this.Numerator * frac.Denominator;
            int numerator2 = frac.Numerator * this.Denominator;

            return new Fraction(numerator1 - numerator2, denominator);
        }

        public Fraction Multiply(Fraction frac)
        {
            return new Fraction(this.Numerator * frac.Numerator, this.Denominator * frac.Denominator);
        }

        public Fraction Divide(Fraction frac)
        {
            if (frac.Numerator == 0) throw new DivideByZeroException();

            return new Fraction(this.Numerator * frac.Denominator, this.Denominator * frac.Numerator);
        }
        #endregion
    }
}