Unity c# 需要帮助理解 switch 语句

Question

I'm trying to understand switch statements and conditionals with them.

Here is the script currently.

Unit thisUnit; <- my reference to the unit stats it has.
int captureStartingHealth;
int captureStartingMana
 
void Start()
{
    captureStartingHealth = thisUnit.currentHP;
    // In start it's the same as thisUnit.maxHP;
    captureStartingMana = thisUnit.currentMP;
    // In start it's the same as thisUnit.maxMP;
}
 
void AssignmentSwitchStatement()
{
    switch (captureStartingHealth)
   {
case int captureStartingHP when captureStartingHealth < (float)captureStartingHealth:
        behaviour = Behaviour.SUPPORT;
        roll = Random.Range(0, 101);
        IncrementSupportRollChances();
        break;
default:
        roll = Random.Range(0, 101);
        DefaultRollChances();
        break;
   }
}

What is the correct syntax for constructing a way to reference when my captureStartingHealth variable is less than 40 for example. When I made the syntax it doesn't allow me to simply use the integer 'captureStartingHealth' instead.. it seems to only work if I make a new integer variable for the case.

So, why is it I can't use my captureStartingHealth integer like this?

switch (captureStartingHealth) // example switch
        {
            case captureStartingHealth when captureStartingHealth < (float)thisUnit.maxHP:
             //execute code
             break;
        }
"

Instead it requires me to make a new integer

case int a when a < conditional

but how do I know when this new int has reached the conditional as true? Like I don't understand how this int "a" works for the switch since it's a local integer that isn't assigned anything right? So for me it's like saying..

case int a (0) when a (0) < (float)thisUnit.maxHP: // execute code

What am I doing wrong here? Probably many things but I honestly don't know why the case needs a new integer instead of using the value I want to compare for the conditional statement.

Answer 1

That first switch code makes absolutely no sense at all!

in

switch(captureStartingHealth)
{
    case int captureStartingHP:
        ...
        break;

    default:
        ...
        break;
}

you make a type check via Pattern Matching and check if captureStartingHealth is an int . Basically like doing

if(captureStartingHealth is int captureStartingHP)
{
    ...
}
else
{
    ...
}

which kind of is equal to doing

if(captureStartingHealth.GetType().IsAssignableTo(typeof(int)))
{
    int captureStartingHP = (int)captureStartingHealth;

    ...
}
else
{
    ...
}

But since captureStartingHealth is an int anyway this is always true and just unnecessary overhead.

Then you anyway throw away the type casted captureStartingHP and compare

captureStartingHealth < (float)captureStartingHealth

Here are two weird things:

• what is the cast to float good for when comparing two int values?
• a < a will never be true ... you have both times the same variable!

---

As was mentioned before if the only check you actually want to do is comparing the two values you rather want to use a simple if - else

// you do this in any case so rather pull it out of the checks in order to write/maintain it only once
roll = Random.Range(0, 101);

if(captureStartingHealth < thisUnit.maxHP)
{
    behaviour = Behaviour.SUPPORT;
    IncrementSupportRollChances();
}
else
{
    DefaultRollChances();
}