title: CS0019 Operator cannot be applied to operands of type 'bool' and 'int'
body: <p>This program is in response to the assignment: </p>
  
  <p>"Create a method named <code>Sum()</code> that accepts any number of integer parameters and
  displays their sum. Write a <code>Main()</code> method that demonstrates that the <code>Sum()</code> method works correctly when passed one, three, five, or an array of ten integers. Save the program as <code>UsingSum.cs</code>."</p>
  
  <p>from Microsoft® Visual C#® 2008, <em>An Introduction to Object-Oriented Programming, 3e, Joyce Farrell</em></p>
  
  <p>My code in the "//step 1:" part is getting the CS0019 error, which states that it cannot be applied to operands of type <code>bool</code> and <code>int</code>.</p>
  
  <p>I highly suspect there are also other problems with this code, but it's a great improvement over what I had four hours ago…  </p>
  
  <pre><code>using System;
  
  public class UsingSum
  {
      public static void Main()
      {
          Sum();
      }
  
      public static void Sum() 
      { 
         // Step 1: Addition of one, three, five
         bool q, r, s;
         int firstTotal, n, o, p;
         string k, l, m;
  
         Console.Write("Type the number 1: ");    
         k = Console.ReadLine();
  
         n = Convert.ToInt32(k);
         q = Convert.ToBoolean(k);
  
         Console.WriteLine();
  
         if (q == 1)
             Console.WriteLine("Input accepted.");
         else if (!(q == 1))
         {
            Console.WriteLine("Error: You didn't type the number 1. Please try again.");
            Console.Write("Type the number 1: ");    
            k = Console.ReadLine();
  
            n = Convert.ToInt32(k);
            q = Convert.ToBoolean(k);
         }
      }
  
      Console.Write("Type the number 3: ");    
      l = Console.ReadLine();
      r = Convert.ToBoolean(l);
      o = Convert.ToInt32(l);
  
      Console.WriteLine();
  
      if (r &lt;= 2 || r &gt;= 4)
      {
         Console.WriteLine("Error: You didn't type the number 3. Please try again.");
         Console.Write("Type the number 3: ");    
         l = Console.ReadLine();
         r = Convert.ToBoolean(l);
         o = Convert.ToInt32(l);
      }
      else
          if (r = 3)
             Console.WriteLine("Input accepted.");
  
      Console.Write("Type the number 5: ");    
      m = Console.ReadLine();
  
      p = Convert.ToInt32(m);
      s = Convert.ToBoolean(m);
  
      Console.WriteLine();
  
      if (s &lt;= 4 || s &gt;= 6)
      {
         Console.WriteLine("Error: You didn't type the number 5. Please try again.");
         Console.Write("Type the number 5: ");    
         m = Console.ReadLine();
  
         p = Convert.ToInt32(m);
         s = Convert.ToBoolean(m);
      }
      else
         if (s = 5)
            Console.WriteLine("Input accepted.");
  
       firstTotal = n + o + p;
  
       Console.WriteLine("{0} + {1} + {2} = {3}", n, o, p, firstTotal); 
  
       // Step 2: Entering integers for array[10]
  
       int a, arrayTotal, b, c, d, e, f, g, h, i, j, unlimited;
  
       Console.Write("Enter first integer for addition: ");
       a = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter second integer for addition: ");
       b = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter third integer for addition: ");
       c = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter forth integer for addition: ");
       d = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter fifth integer for addition: ");
       e = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter sixth integer for addition: ");
       f = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter seventh integer for addition: ");
       g = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter eighth integer for addition: ");
       h = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter ninth integer for addition: ");
       i = Convert.ToInt32(Console.ReadLine());
       Console.Write("Enter tenth integer for addition: ");
       j = Convert.ToInt32(Console.ReadLine());
  
       arrayTotal = a + b + c + d + e + f + g + h + i +j; 
  
       Console.WriteLine("The total of {0} + {1} + {2} + {3} + {4} + {5} + {6} + {7} + {8} + {9} = {10}",
       a, b, c, d, e, f, g, h, i, j, arrayTotal);
  
       // Step 3: Unlimited array addition
       int[] arrayTwo;
       int total, y;
       string ADD, x;
  
       while(Console.Write("Enter an integer for addition, or type ADD to calculate the sum: "))
       {
          x = Console.ReadLine();
          y = Convert.ToInt32(x);
  
          if (x == ADD)
             Console.WriteLine("Calculating the total sum");
       }   
  
       for (y = 0; y &lt; arrayTwo.Length; ++y)
       {
          total = arrayTwo[y] + arrayTwo[y];              
          ++arrayTwo[y];
          Console.WriteLine("========================");
          Console.WriteLine("=/n= The total is: {0} =/n=", total);
          Console.WriteLine("========================");
       }                                         
    }
  }
  </code></pre>