servo control

#include <Servo.h>
Servo myservo;
int duty_cycle=0;


void setup()      //This function executes only once
{ 
  // myservo.attach(3);  
  pinMode(3, OUTPUT); 
}

void loop()     // This function executes repeatedly
{
 while (1) {
    readinput();
    delay(100);
    servocontrol();
  }
  
}

int readinput()     // This function executes repeatedly
{
  int addata = analogRead(0);
 
  int a = .7;
  int b = 2.4;
  int freq = 40; 
 
  //now we want to take the input and map it to [a,b] for our pulse width 
  float scale = ((float)(b-a))/(1023-0);

 
return scale*addata*freq ;
}
void servocontrol()
{
  int duty_cycle = readinput();
 // myservo.write(pwm);
 analogWrite(3, duty_cycle); 
}