CS0019 Operator cannot be applied to operands of type 'bool' and 'int'

Nooob picture Nooob · Oct 24, 2010 · Viewed 100.2k times · Source

This program is in response to the assignment:

"Create a method named Sum() that accepts any number of integer parameters and displays their sum. Write a Main() method that demonstrates that the Sum() method works correctly when passed one, three, five, or an array of ten integers. Save the program as UsingSum.cs."

from Microsoft® Visual C#® 2008, An Introduction to Object-Oriented Programming, 3e, Joyce Farrell

My code in the "//step 1:" part is getting the CS0019 error, which states that it cannot be applied to operands of type bool and int.

I highly suspect there are also other problems with this code, but it's a great improvement over what I had four hours ago…

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 <= 2 || r >= 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 <= 4 || s >= 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 < arrayTwo.Length; ++y)
     {
        total = arrayTwo[y] + arrayTwo[y];              
        ++arrayTwo[y];
        Console.WriteLine("========================");
        Console.WriteLine("=/n= The total is: {0} =/n=", total);
        Console.WriteLine("========================");
     }                                         
  }
}

Answer

Fr&#233;d&#233;ric Hamidi picture Frédéric Hamidi · Oct 24, 2010

You can't write (q == 1) in C#, because q is a bool and 1 is an int.

q can only be compared to another boolean expression, e.g. true, false, another boolean variable, etc.