fluctuating output of adc of pic18f4550.

#define USE_OR_MASKS
#include "delays.h"
#include "p18f4550.h"
#include "adc.h"
#include "math.h"


#if defined(_18F4550)		//If the selected device if PIC18F46J11, then apply below settings else user will have to set
#pragma config OSC=HS, FCMEN=Off, WDT=OFF, IESO=OFF, XINST=OFF, LVP=OFF 
#endif


unsigned int ADCResult=0;
float voltage_x=0;
float theta_x = 0;
float degree_x = 0;

float voltage_y=0;
float theta_y = 0;
float degree_y = 0;



void main(void)
{

    unsigned char channel=0x00,config1=0x00,config2=0x00,config3=0x00,portconfig=0x00,i=0;
    unsigned int final_output,h,d,X=0;
    d = 1;

    
    
  
	    h = 0;
	TRISD = 0;
    PORTD = 0xFF;
    TRISAbits.TRISA0 = 1; //RA) as Analog i/p
    PORTAbits.RA0 = 1;
    CloseADC();  
    Delay10TCYx(4);
//--initialize adc---
/**** ADC configured for:
    * FOSC/32 as conversion clock
    * Result is right justified
    * Aquisition time of 2 TAD
    * Channel 0 for sampling
    * ADC interrupt off
    * ADC reference voltage from VDD & VSS
*/
   

//---initialize the adc interrupt and enable them---
    ADC_INT_DISABLE();

//---sample and convert----
   
     while (d=1)
    {
      for ( i=0;i<3;i++)

     {
       
       if (i==0)
     {
         



      config1 = ADC_FOSC_16 | ADC_RIGHT_JUST | ADC_2_TAD ;
    config2 = ADC_CH0 | ADC_INT_OFF | ADC_REF_VDD_VSS ;
    portconfig = ADC_2ANA  ;
    OpenADC(config1,config2,portconfig);

   ADC_INT_DISABLE();


      Delay10TCYx(5);
  
    ConvertADC();
    
    while(BusyADC());
  
    Delay10TCYx(4);
	ADCResult = ReadADC();
    
    final_output = ADCResult;
   
	voltage_x = (final_output*5.0)/1023;

    
    theta_x = asin ((voltage_x-1.65)/0.8);
 
    degree_x = theta_x * 57.2957795;
    
	//PORTD = theta;

    CloseADC();         //turn off ADC
   
       Delay10TCYx(100);
     










     
     

     } 
      else if (i==1)
     {
  




 config1 = ADC_FOSC_16 | ADC_RIGHT_JUST | ADC_2_TAD ;
    config2 = ADC_CH1 | ADC_INT_OFF | ADC_REF_VDD_VSS ;
    portconfig = ADC_2ANA  ;
    OpenADC(config1,config2,portconfig);

   ADC_INT_DISABLE();


      Delay10TCYx(5);
    
    ConvertADC();
    
    while(BusyADC());
   
	//{ADCResult = (unsigned int) ReadADC();
  
    Delay10TCYx(4);
	ADCResult = ReadADC();
    
    final_output = ADCResult;
   
	voltage_y = (final_output*5.0)/1023;

    
    theta_y = asin ((voltage_y-1.65)/0.8);
 
    degree_y = theta_y * 57.2957795;
    
	//PORTD = theta;

    CloseADC();         //turn off ADC
    
   Delay10TCYx(100);







     }


    break;
    } 



     }

}