Cannot implicitly convert type 'bool' to 'int'

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Hi I get an error:
Cannot implicitly convert type 'bool' to 'int'
anyway the program executes with the errors but I dont know how to fix it.
Here is the code snippet:

// switch on the value of inputInt
                switch (inputInt)
                {
                    case (inputInt == 0):
                        Console.WriteLine("your input is zero.");
                        goto repeat;
                    case (inputInt % 2 != 0):
                        Console.WriteLine("your input is odd.");
                        goto repeat;
                    case (inputInt % 2 == 0):
                        Console.WriteLine("your input is even.");
                        goto repeat;
                    case (inputInt % 10 == 0):
                        Console.WriteLine("your bla bla..");
                        goto repeat;
                    case (inputInt > 100):
                        Console.WriteLine("your input is bla bla..");
                        goto repeat;
                }

I do not understand what is the problem. Can't we have formulas and equations into the case statement?
Best regards

It is a schools assignment.
Task number one was to do this using if-else statements, it is ok.
Task number two is to do the same program, using a switch statement...
It is going to be more code, just to accomplish it with a switch statement.

Otherwise I also don't thing it is efficient to use a switch statement here.
The tasks themselves:

1. "Create a program that prompts user for an input, accepts an integer, then evaluates whether that input is zero, odd or even, a multiple of 10, or too large (more than 100) by using multiple levels of 'if' statements."

2."Rewrite the the program from the previous exercise to do the same work with a switch statement...

-----------------------------------------------------------------

why do you nest them?

i wast thinking of a way to have to outputs with a switch statement.
for example a number that is multiple of 10 is also an even number.
so it is gonna be nice to have to console outputs:
"the num is multiple of 10"
"the num is even"
but i got realy bored for today, and I suspect it is not possible only with a switch statements, even nested ones.

Posted 11-Mar-10 5:54am

emosms

Updated 11-Mar-10 10:21am

Christian Graus

v3

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7 solutions

Solution 1

Your code is soooo wrong!
If inputInt is an int, then the case values should be int consts, ex: 0, 1, 10..., not bool (true of false) expressions.

Posted 11-Mar-10 6:09am

Toli Cuturicu

Updated 11-Mar-10 6:10am

v2

Solution 2

Toli is exactly right. Your switch statement is told to evaluate an Int. Think of the switch as an easier to write series of If Then statements. In your case, it would equate to:

C#

if (inputInt == (inputInt == 0))
{
    ...;
}
else if (inputInt == (input %2 != 0))
{
    ...;
}
...

So, it fails because you're asking it if an int is equal to a boolean value.

From msdn:
"In C++, a value of type bool can be converted to a value of type int; in other words, false is equivalent to zero and true is equivalent to nonzero values. In C#, there is no conversion between the bool type and other types. For example, the following if statement is invalid in C#:"

Posted 11-Mar-10 6:18am

William Winner

Solution 3

It is a schools assignment.
Task number one was to do this using if-else statements, it is ok.
Task number two is to do the same program, using a switch statement...
It is going to be more code, just to accomplish it with a switch statement.

Otherwise I also don't thing it is efficient to use a switch statement here.
The tasks themselves:

1. "Create a program that prompts user for an input, accepts an integer, then evaluates whether that input is zero, odd or even, a multiple of 10, or too large (more than 100) by using multiple levels of 'if' statements."

2."Rewrite the the program from the previous exercise to do the same work with a switch statement...

Posted 11-Mar-10 6:22am

emosms

Solution 5

why do you nest them?

i wast thinking of a way to have to outputs with a switch statement.
for example a number that is multiple of 10 is also an even number.
so it is gonna be nice to have to console outputs:
"the num is multiple of 10"
"the num is even"
but i got realy bored for today, and I suspect it is not possible only with a switch statements, even nested ones.

Posted 11-Mar-10 9:11am

emosms

Solution 7

switch (n % 10)
{
    //is a multiple of 10
    case 0:
        Console.WriteLine("Is a multiple of 10");
        break;
    //check if odd
    case 1:
    case 3:
    case 5:
    case 7:
    case 9:
        Console.WriteLine("Is Odd");
        break;
    //even
    default:
        Console.WriteLine("Is Even");
        break;
}

You tricked it man! That is why there is an additional requirement to evaluate for a max value (is > 100).
Then for (input % 10) when (input > 100) we have a limited number of cases: case 1,3,5,7,9. The modulus is an odd number, so odd is the dividend.
Thank you for helping me understand the switch statement logics.
Best Regards
P.S. as about if the assignment is crazy - it is challenging to explore the language's features.
Otherwise this particular solution (switch) is maybe not pragmatic to quick solve a real task.

Posted 12-Mar-10 3:00am

emosms

Updated 12-Mar-10 4:45am

v2

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Christian Graus · Accepted Answer · 2010-03-11T10:24:00

Your basic issue is that you don't understand switch statements. A switch statement is not a case. To do it with a case statement you'd need to do this:

C#

switch (inputInt)                
{
                    case 0: 
                       Console.WriteLine("your input is zero.");           
             break;   
               case 2:
               case 4:
               case 6:
               case 8: // etc
Console.WriteLine("your input is even.");                        
               break;
//etc

I agree, this is not a good place to use a case statement, but this is almost certainly what your teacher wants to see. The important points:

1 - a case statement means you list the cases you want to catch, a case is NOT a place to write evaluative code, as you did
2 - there is no reason to use goto here, or, basically, almost anywhere. I have never used goto in my code. It makes your code unreadable and is unnecessary.
3 - you can put more than one case in a block, so I did 2,4,6,8, etc, then put the one block of code that executes for all those cases.

I should add a couple of things:

1 - we don't normally do people's homework. I was happy to help you b/c you were trying to do your own work, not just asking for a solution, but it does seem to me like you were struggling a bit with the way case statements work, and I'd recommend you also talk to your teacher about this, to make sure it's clear in your mind.

2 - you should not push the 'answer' button to ask more questions. You should edit your post ( I copied your replies into your main post ), or use the forum under the answers section.

William Winner · Accepted Answer · 2010-03-11T07:21:00

God...yeah, that's not really a prime case for a switch statement in my opinion.

The best, I could think of doing would be nested switch statements like:

C#

switch (n)
{
    //check if zero
    case 0:
        Console.WriteLine("Is Zero");
        break;
    //not zero
    default:
        //check if it's greater than 100
        //Math.Floor will round down (so 0 if less than 100)
        switch ((int)Math.Floor((double)(n / 100)))
        {
            //less than 100
            case 0:
                //run a mod 10 (0 is multiple of 10)
                switch (n % 10)
                {
                    //is a multiple of 10
                    case 0:
                        Console.WriteLine("Is a multiple of 10");
                        break;
                    //check if odd
                    case 1:
                    case 3:
                    case 5:
                    case 7:
                    case 9:
                        Console.WriteLine("Is Odd");
                        break;
                    //even
                    default:
                        Console.WriteLine("Is Even");
                        break;
                }
                break;
            default:
                Console.WriteLine("> 100");
                break;
        }
        break;
}

[Modified]
If you want to also output "Is even" if it's a multiple of 10, then just add another Console.WriteLine(...)

Cannot implicitly convert type 'bool' to 'int'

7 solutions

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Solution 2

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