View difference between Paste ID: tKdzRt2J and LAPvziBt

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 
-namespace AddSubstractMultiplyPolynomial
+namespace AddSubtractMultiplyPolynomials
 {
     class Polynomial
     {
         private List<double> coefficients;
 
         public Polynomial()
         {
             coefficients = new List<double>();
         }
 
         public int PolynomialDegree
         {
             get
             {
                 return coefficients.Count - 1;
             }
         }
 
         public double this[int index]
         {
             get
             {
                 if (index >= 0 && index < coefficients.Count)
                 {
                     return coefficients[index];
                 }
                 else
                 {
                     return 0.0;
                 }
             }
 
             set
             {
                 if (index >= 0 && index < coefficients.Count)
                 {
                     coefficients[index] = value;
                 }
             }
         }
 
         private void AddCoefficient(double coef)
         {
             coefficients.Add(coef);
         }
 
         public void ReadPolynomial()
         {
             Console.Write("Enter the polynomial degree: ");
             int polynomialDegree = int.Parse(Console.ReadLine());
 
             Console.WriteLine("Enter the polynomial coefficients:");
             for (int i = 0; i <= polynomialDegree; ++i)
             {
                 coefficients.Add(double.Parse(Console.ReadLine()));
             }
         }
 
         private void Normalize()
         {
             if (PolynomialDegree >= 0)
             {
                 while (coefficients[PolynomialDegree] == 0.0)
                 {
                     coefficients.RemoveAt(PolynomialDegree);
 
                 }
             }
         }
 
         public static Polynomial operator +(Polynomial x, Polynomial y)
         {
             int biggerDegree = Math.Max(x.PolynomialDegree, y.PolynomialDegree);
             Polynomial result = new Polynomial();
 
             double tmp = 0.0;
             for (int i = 0; i <= biggerDegree; ++i)
             {
                 tmp = 0.0;
                 if (i <= x.PolynomialDegree)
                 {
                     tmp += x[i];
                 }
                 if (i <= y.PolynomialDegree)
                 {
                     tmp += y[i];
                 }
 
                 result.AddCoefficient(tmp);
             }
 
             result.Normalize();
             return result;
         }
 
         public static Polynomial operator -(Polynomial x)
         {
             Polynomial result = new Polynomial();
             for (int i = 0; i <= x.PolynomialDegree; ++i)
             {
                 result.AddCoefficient(-x[i]);
             }
             return result;
         }
 
         public static Polynomial operator -(Polynomial x, Polynomial y)
         {
             Polynomial result = x + (-y);
             return result;
         }
 
         public static Polynomial operator *(Polynomial x, Polynomial y)
         {
             Polynomial result = new Polynomial();
             for (int i = 0; i <= x.PolynomialDegree; ++i)
             {
                 for (int j = 0; j <= y.PolynomialDegree; ++j)
                 {
                     if (result.PolynomialDegree < i + j)
                     {
                         result.AddCoefficient(0.0);
                     }
                     result[i + j] += x[i] * y[j];
                 }
             }
             result.Normalize();
             return result;
         }
 
         public override string ToString()
         {
             StringBuilder result = new StringBuilder("");
             for (int i = PolynomialDegree; i >= 0; --i)
             {
                 if (i != PolynomialDegree)
                 {
                     result.Append(" ");
                 }
                 result.Append(coefficients[i].ToString());
             }
             return result.ToString();
         }
     }
-    class AddSubstractMultiplyPolynomial
+    class AddSubtractMultiplyPolynomial
     {
         static void Main(string[] args)
         {
             Polynomial a = new Polynomial();
             Polynomial b = new Polynomial();
 
             a.ReadPolynomial();
             b.ReadPolynomial();
 
-            Polynomial r = a * b;
+            Polynomial r = a + b;
-            Console.WriteLine(r.ToString());
+            Console.WriteLine("Addition: " + r.ToString());
             r = a - b;
             Console.WriteLine("Subtraction: " + r.ToString());
             r = a * b;
             Console.WriteLine("Multiplication: " + r.ToString());
 
         }
     }
 }