Arduino code to control an analog DC motor, regulated by a potentiometer

// Control an analog DC motor, regulated by a potentiometer
int analogInput = 0;
int motorSpeed = 0;

void setup(){
  pinMode (3, OUTPUT);
}

void loop(){
  analogInput = analogRead(A0);
  motorSpeed =  analogInput/4;
  analogWrite (3, motorSpeed);
}

// Control a servo motor
#include 

Servo myServo;

int analogInput = 0;
int motorPosition = 0;

void setup(){
  myServo.attach(9);
}

void loop(){
  analogInput = analogRead(A0);
  motorPosition =  map (analogInput, 0,1023,  0,180);
  analogWrite (3, motorSpeed);
}

Breadboard diagram:

Make a servo motor turn back and forth:

#include 

Servo myServo;

int analogInput = 0;
int motorPosition = 0;

void setup(){
 myServo.attach(9);
}

void loop(){
 //analogInput = analogRead(A0);
 //motorPosition = map(analogInput, 0, 1023, 0, 180);
 //myServo.write(motorPosition);

 for(motorPosition = 0; motorPosition =1; motorPosition--){
  myServo.write(motorPosition);
  delay(10);
 }
}