Case invalid expression term

Question

What’s wrong with this switch case statement?
It throws: “invalid expression term <“
profit is an integer.

switch(profit)
{
case == 0:
Console.WriteLine("Broke Even");
break;

case < 0:
Console.WriteLine("Loss");
break;

case > 0:
Console.WriteLine("Profit");
break;

default:
Console.WriteLine("Sum ting wong");
break;
}

Answer 1

1) You can't use conditional checking inside a switch case, you can only use numbers like the below snippet:
switch(profit){
case 0:
Console.WriteLine("Broke even");
break;
.....
}

Also as a side note, to check if a variable is equal to a value, use == and not =. = is only used to assign a value to a variable.

Answer 2

You might find switch expression helpful for these types of scenario. https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/switch-expression

But I personally would prefer use of `if...else if...else` where exists a possibility that condition(s) are involved in evaluation, more compatible disregarding the programming language selection.

Answer 3

If you wish, you can combine 😎:
switch(profit){
case 0:
Console.WriteLine("Broke Even");
break;
default:
if(profit < 0)
Console.WriteLine("Loss");
else if(profit > 0)
Console.WriteLine("Profit");
else
Console.WriteLine("Sum ting wong");
break;
}

Answer 4

Referring to MS Docs it should be possible to use conditional checking on cases.
I tried to run the example code on the playground and received the same error.

Just found out, that pattern matching is released with c# 7.0
C# 6.0 and earlier doesn’t support this feature.

https://docs.microsoft.com/de-de/dotnet/csharp/language-reference/statements/selection-statements

Answer 5

Yes, the new version of C# has expanded the functionality a lot. ☺️

Answer 6

You may try something like this

try {
switch (profit/Math.Abs(profit))
{
case 1:
Console.WriteLine("Profit");
break;
case -1:
Console.WriteLine("Loss");
break;
default :
Console.WriteLine("Something wrong!");
break;
}
}
catch (DivideByZeroException e) {
Console.WriteLine("Broke Even");
}