You need to have a semicolon at the end of each expression.
byte myvar; // semicolon needed here
void setup()
{
myvar = 10; // and here
Serial.begin (9600);
}
void loop()
{
if (10 == HIGH)
{
Serial.println (myvar);
}
}
This code will compile but wont print anything because
if (10 == HIGH)
will never be true, what did you want to do here?