what wrong with my if statement

Projects Programming
1

Hi everyone a newbee programming question, why do i get errors trying to compile with my if statement the error in the ardunio complier is " expected initializer before 'if'"

the 'smode' variable is delared at the top of my code with pin assiginments and stuff as a global variable

#include <avr/pgmspace.h>
#define bl_inc 10
#include <OneWire.h>
#include <DallasTemperature.h>
// Data wire is plugged into port 3 on the Arduino
#define ONE_WIRE_BUS 3
#define TEMPERATURE_PRECISION 9
// mills() delay
unsigned long timer1 = 0;
///
        int motorPin = 11;//pwm fan control
  const int vent1Pin = 8;//Summer damper
  const int vent2Pin = 9; //roof damper
  const int vent3Pin = 7;//heat transfer
  int smode = 0;

then at the top of my loop code i try to test the 'smode' variable with a simple if else statement.

void loop()

if (smode == 0)
{
     digitalWrite(9, HIGH);
}
else{
 digitalWrite(9,LOW);
}

can someone please point out my syntax error because i read the code as i have assigned the variable 'smode' to '0' up at the top of my code as a global variable then in the loop the if statement should be comparing if 'smode' is still '0' then it can do stuff? but i cant compile with the if statement because of the complier error.

sketch_dec08a:120: error: expected initializer before 'if'
sketch_dec08a:124: error: expected unqualified-id before 'else'

this the lines with my if statement that contains the error

cheers for your help

2

That error means there is something wrong before the if statement. In your case you have not put { } round your loop() function body.

3

thanks grumpy!

4

Side note: I think you can actually get rid of the if statement entirely and just do this:

void loop()
{
    digitalWrite( 9, !smode );
}

As I understand it, booleans are actually just integers where 0 is equivalent to false and anything else equals true. So if smode is zero it reads as false, and then the ! reverses it to true (non-zero), which digitalWrite will read as HIGH. Likewise, if it's not zero (true), the ! will reverse it to zero (false) and digitalWrite will see it as LOW.

5

you need have the loop() section in {}.
void loop()
{

// your if statement here

}