Motor position control using single input encoder

Using Arduino Programming Questions
1

I am trying to control a 24V DC motor position using a single input encoder. The encoder wheel has got 30 spikes on it. It is connected to the interrupt 0 pin. I am trying to move the motor first to a forward position (theta1 = 120deg) from a home position. Then back to the home position from where it has to be moved to a backward position (theta1D = 90deg). I have written a code for the same but while compiling it gives an error on line 6 as
error : expected unqualified-id before '{' token
The code is as shown below:

int encoder1Pin = 2;
int motor1PinA = 3;
int motor1PinB = 4;
volatile int encoder1Pos = 0;

{
 void setup ()
 {
   pinMode(encoder1Pin,INPUT);
   pinMode (motor1PinA,OUTPUT);
   pinMode (motor1PinB,OUTPUT);
   attachInterrupt(0, ISR, CHANGE);
   int theta1 = 120;
   int theta1D = 90;
 }
    int motor1Forward();
   {
     digitalWrite(motor1PinA,HIGH);
     {
     if(encoder1Pos*6 == theta1);
     }
     digitalWrite(motor1PinA,LOW);
     encoder1Pos = 0;
   }
   int motor1Home();
   {
     digitalWrite(motor1PinB,HIGH);
     {
       if(encoder1Pos*6 == theta1);
     }
     digitalWrite(motor1PinB,LOW);
     encoder1Pos = 0;
   }
   int motor1Backward();
   {
      digitalWrite(motor1PinB,HIGH);
     {
       if(encoder1Pos*6 == theta1D);
     }
     digitalWrite(motor1PinB,LOW);
     encoder1Pos = 0;
   }
}
{
   void ISR()
   {
     encoder1Pos++
   }
}
2

The line that it errors on has an opening brace on it. Why ?

The outer braces in this code section need to go as well

{
  void ISR()
  {
    encoder1Pos++
  }
}

As do the semi-colons at the end of the function names such as this one (and others)

int motor1Home();

There may be other problems but I stopped looking.

3

Thanks UKHeliBob..
I modified the code as shown below. But still errors.

int encoder1Pin = 2;
int motor1PinA = 3;
int motor1PinB = 4;
volatile int encoder1Pos = 0;
int theta1 = 120;
int theta1D = 90;

void setup() {
  pinMode(encoder1Pin,INPUT);
  pinMode (motor1PinA,OUTPUT);
  pinMode (motor1PinB,OUTPUT);
  attachInterrupt(0, encoder1svc, CHANGE);
}

void loop() 
{
int motor1Forward()
{
  digitalWrite(motor1PinA,HIGH);
  {
    if(encoder1Pos*6 == theta1);
  }
  digitalWrite(motor1PinA,LOW);
  encoder1Pos = 0;
}
int motor1Home()
{
  digitalWrite(motor1PinB,HIGH);
  {
    if(encoder1Pos*6 == theta1);
  }
  digitalWrite(motor1PinB,LOW);
  encoder1Pos = 0;
}
int motor1Backward()
{
  digitalWrite(motor1PinB,HIGH);
  {
    if(encoder1Pos*6 == theta1D);
  }
  digitalWrite(motor1PinB,LOW);
  encoder1Pos = 0;
}
void encoder1svc()
{
  encoder1Pos++;
}
}
4

You have got several function definitions within the loop() function. In fact there is nothing in the loop() function apart from function definitions.