Methods v. Subroutines

I've been trying to find some information on methods / method calls, I think that's what it is.

Isn't that equivalent to GOTOs/GOSUBs, branching to subroutines, repetitive operations? Just to break it down - say a pin needed to be toggled often, instead of writing that operation over and over, isn't there a way to write that once and then jump over to a subroutine and back? I haven't found anything concise, maybe my terms are imprecise.

This is an absurd example, but still:

void loop()
{
   digitalWrite(13, HIGH);
   delay(500)
   senditlow;
   digitalWrite(13, HIGH);
   delay(1000)
   senditlow;
}

void senditlow()
{
   digitalWrite(13, LOW);
   delay(2000);
}

Isn't that equivalent to GOTOs/GOSUBs, branching to subroutines, repetitive operations?

GOSUB - yes, GOTO - no.

A subroutine and function are nearly identical. The difference is historic, more than anything. A subroutine does something, but returns no value. A function does something and returns a value. So, loop() is a subroutine, and Serial.read() is a function.

isn't there a way to write that once and then jump over to a subroutine and back?

Yes, just as you showed.

OK... Well, I "upload" this to my Nano and it just stays with D13 on:

void setup() 
{                
  pinMode(13, OUTPUT); 
}

void loop()
{
   digitalWrite(13, HIGH);
   delay(500);
   senditlow;
   digitalWrite(13, HIGH);
   delay(1000);
   senditlow;
}

void senditlow()
{
   digitalWrite(13, LOW);
   delay(1000);
}
   senditlow;

This is wrong. Try:

   senditlow();

Bingeaux!

Thanks, PaulS.