'else' without a previous 'if'

Projects Programming
1

My code

#include <Servo.h>

#define trig 2
#define echo 4
#define right 11
#define front 12
#define left 13

Servo servo;

void setup() {
  servo.attach(9);
  pinMode (trig, OUTPUT);
  pinMode (echo, INPUT);
  Serial.begin (9600);
  
  }

void loop() {
  
  //All
digitalWrite(trig, LOW);
delayMicroseconds(2);
digitalWrite(trig, HIGH);
delayMicroseconds(10);
digitalWrite(trig, LOW);

  long t = pulseIn(echo, HIGH);

  long inches = t / 74 / 2;
  long cm = t / 29 / 2;
  
  servo.write(90);
  delay(1000);


  if (cm > 10){ // front check
    digitalWrite(11, HIGH);
    servo.write(90);
    digitalWrite(front, HIGH);
  }
  else{
    servo.write(20); // turn to left
    delay(100);
  }

  if (cm > 10);{ //check left 
    digitalWrite(left, HIGH);
  }
  else{
    servo.write(180); //turn to right
    delay(100);
  }
  
  if (cm > 10){ // check right
  digitalWrite(right, HIGH);
  }
  else{
    digitalWrite(front, HIGH);
    digitalWrite(front, LOW);
    digitalWrite(front, HIGH);
    digitalWrite(front, LOW);
    digitalWrite(front, HIGH);
    digitalWrite(front, LOW);
    digitalWrite(front, HIGH);
    digitalWrite(front, LOW);
  }

}

Error

exit status 1
'else' without a previous 'if'

What's that?

2

This is your full error; it indicates the line where it fails.

C:\Users\WIMSTU~1\AppData\Local\Temp\arduino_3431cf36d2090c05fd30f5c5b5b2b264\sketch_oct28a.ino: In function 'void loop()':

sketch_oct28a:50: error: 'else' without a previous 'if'

   else{

   ^

Using library Servo at version 1.1.1 in folder: C:\Program Files (x86)\Arduino\libraries\Servo 
exit status 1
'else' without a previous 'if'

The IDE even highlights the line where the error occurs. And the section of the code

  if (cm > 10);{ //check left
    digitalWrite(left, HIGH);
  }
  else{
    servo.write(180); //turn to right
    delay(100);
  }

Looking at that part, your if statement ends with a semi-colon.

PS
Please edit your post and change the [quote] and [/quote] to [code] and [/code].

3

sterretje:
This is your full error; it indicates the line where it fails.

C:\Users\WIMSTU~1\AppData\Local\Temp\arduino_3431cf36d2090c05fd30f5c5b5b2b264\sketch_oct28a.ino: In function 'void loop()':

sketch_oct28a:50: error: 'else' without a previous 'if'

else{

^

Using library Servo at version 1.1.1 in folder: C:\Program Files (x86)\Arduino\libraries\Servo
exit status 1
'else' without a previous 'if'



The IDE even highlights the line where the error occurs. And the section of the code

if (cm > 10);{ //check left
    digitalWrite(left, HIGH);
  }
  else{
    servo.write(180); //turn to right
    delay(100);
  }



Looking at that part, your if statement ends with a semi-colon.


PS
Please edit your post and change the `[quote] and [/quote] to [code] and [/code]`.

ok.
Thanx..

4

The "if" can only contain one statement. That semicolon counts as your one statement. What the compiler sees is:

  if (cm > 10)
    ;

  { //check left
    digitalWrite(left, HIGH);
  }
  else {
    servo.write(180); //turn to right
    delay(100);
  }