A line of code that i dont understand?

I am trying to make an Arduino Based calculator that just works with a Keypad, Arduino Uno board and a LCD screen. I found a code online and i tried to understand the code yet i diditn quite understand this part. Can anyone help?

second == 0 ? lcd.print(“Invalid”) : total = (float)first / (float)second;

 if (second == 0)
    lcd.print("Invalid") ;
else
    total = (float)first / (float)second;

Ternary operator.

I think that's about one of the worst examples of use/abuse of the conditional operator I could think of. Sure it's legal C, but IMHO it adds nothing to readability and only serves to obfuscate. Added to that one of the expressions has a side effect (printing to the LCD).

No wonder the OP was confused...

Normally you'd see it replacing code like this...

if (a >= b)
{
  max = a;
}
else
{
  max = b;
}

Which you can write more compactly as...

max = (a >= b) ? a : b;

Edit: It's A ternary operator (the only one C has) and not THE ternary operator. Ternary just means 3 arguments, as compared to the more usual binary (two arguments, +, *, > etc) and unary (!, ~, etc) that we are used to.

I try to do it But now still confused

geosixs:
I try to do it But now still confused

Confused about what?

acanyasar: I am trying to make an Arduino Based calculator that just works with a Keypad, Arduino Uno board and a LCD screen. I found a code online and i tried to understand the code yet i diditn quite understand this part. Can anyone help?

second == 0 ? lcd.print("Invalid") : total = (float)first / (float)second;

This is just code that produces an error when you try to divide by 0. If you do you get the reply “Invalid”.

Edit to fix autocorrect

Since you cannot share something amongst nothing, division by zero is not allowed.

geosixs is NOT the OP