problem in driving the internal ADC of PIC18F4550

#include<htc.h>
#include<string.h>
#define _XTAL_FREQ 20000000


#define rs PORTAbits.RA1
#define en PORTAbits.RA2
#define lcdport LATB

void lcd_ini();
void lcdcmd(unsigned char);
void lcddata(unsigned char);
void adc_con(unsigned int);
void adc_init();

unsigned char data[20]="ADC OUTPUT=";
unsigned int digital_out[10],avg_output=0,temp;
unsigned int i=0;


void main()
{
    TRISA=0x01;        // Configure RA0 as input pin
    LATA=0;
    TRISB=0;        // Configure Port B as output port
    LATB=0;
    TRISD=0;
    LATD=0;
	ADCON0 = 0x00;
	ADCON1 = 0b00001111;
	CMCON = 0x07;
    lcd_ini();               // LCD initialization
    while(data[i]!='\0')
    {
        lcddata(data[i]);      // Call lcddata function to send character one by from 'data' array
        i++;
    }
	
   adc_init();        //ADC Initialization

    while(1)
    {
        temp=0;
        for(i=0;i<10;i++)
        {
            /*ADCON0|=(1<<GO);                              // Start A/D conversion
            while(!(ADCON0 & (1<<GO)));*/                   // Wait until conversion gets over
			ADCON0=0x03;
			while(GO!=0);
			digital_out[i]=((ADRESL)|(ADRESH<<8));        // Store 10-bit output into a 16-bit variable
            __delay_ms(20);
			temp=temp+digital_out[i];
        }
        avg_output=temp/10;                           // Take average of ten digital values for stablity
        adc_con(avg_output);                          // Function to convert the decimal vaule to its corresponding ASCII

    }
}


void adc_init()
{
    ADCON1=0x0E;                            // Make RA0/AN0 pin as analog pin (Other pins remain to be digital I/O)
    ADCON0=0x00;                            // Select Channel0 & ADC off
    ADCON2=0x8A;                            // Left justified, 2TAD acquiciation time, Fosc/32 clock option
    ADCON0=0x01;                      // Enable ADC
}


void lcd_ini()
{
    lcdcmd(0x38);        // Configure the LCD in 8-bit mode, 2 line and 5x7 font
    lcdcmd(0x0C);        // Display On and Cursor Off
    lcdcmd(0x01);        // Clear display screen
    lcdcmd(0x06);        // Increment cursor
    lcdcmd(0x80);        // Set cursor position to 1st line, 1st column
}


void adc_con(unsigned int adc_out)
{
    unsigned int adc_out1;
    int i=0;
    char position=0xC1;

    for(i=0;i<=3;i++)
    {
        adc_out1=adc_out%10;                     // To exract the unit position digit
        adc_out=adc_out/10;
        lcdcmd(position);
        lcddata(48+adc_out1);                    // Convert into its corresponding ASCII
        position--;

    }
}


void lcdcmd(unsigned char cmdout)
{
    lcdport=cmdout;        //Send command to lcdport=PORTB
    rs=0;                        
   // rw=0;
    en=1;
    __delay_ms(10);
    en=0;
}


void lcddata(unsigned char dataout)
{
    lcdport=dataout;    //Send data to lcdport=PORTB
    rs=1;
    //rw=0;
    en=1;
    __delay_ms(10);
    en=0;
}