Digital voltmeter with PIC16F877A and LCD

#include <16f877A.h> //Header declaration for pic used
#DEVICE ADC=10   //definition of ADC bits for conversation purpose
//Fuses definition for the PIC

#fuses HS     //definition of the quartz in use High Frequency =4MHZ
#fuses NOWDT  //Disable internal Timer watchdog
#fuses NOLVP   //Disable programmation at low voltage 
#fuses NODEBUG   //disable test of codes at runtime
#fuses NOCPD   //Avoid protection of codes
#use delay(clock=4M)  //Set the values of Quartz to use

//Definition of pins for connecting the LCD:Light Crystal Display

#define LCD_DATA4    PIN_D4
#define LCD_DATA5    PIN_D5
#define LCD_DATA6    PIN_D6
#define LCD_DATA7    PIN_D7

#define LCD_RW_PIN      PIN_D3
#define LCD_ENABLE_PIN   PIN_D1
#define LCD_RS_PIN       PIN_D2
#include <lcd.c>
 float  volt1,volt2; //Variable declaration


void main() //Initialization of the main function
{
set_tris_d(0x00); //definition of ports 
lcd_init(); //Initialization of the LCD to be used
  
   delay_us(5); //set of a delay of 5uS for ADC to start operating
   setup_adc_ports(AN0);  //Set the pin where input is connected
   Setup_adc(ADC_CLOCK_INTERNAL);   //set the clock used by the internal ADC Module
   set_adc_channel(0); //set the channel from which the ADC will be reading the data from
   setup_vref(FALSE); //use of 5V of the power supply as a reference voltage
 
   while(TRUE)  //define the endless loop for measuring the voltage
   {
      delay_us(10);    //set a simple delay for the ADC to start reading 
      read_adc(ADC_START_ONLY);//Start reading the ADC value 
      
      delay_us(2); //set a simple delay for the ADC to start reading 
      volt1=read_adc();//start reading and  store the value in variable volt1
      
       volt2=(volt1*4.88)/1023;  //conversion to decimal number     
      
      
      
      if(volt2==0)//Condition for displaying the text before priniting out on the LCD
      {
      delay_ms(20);
      lcd_gotoxy(2,1);
      printf(lcd_putc,"vin is needed!!");    //printing the text on the LCD  
      }
      else//in case the input is connected the value has to be printed out here below
      lcd_gotoxy(1,1);
      printf(lcd_putc,"\connected vin is:");
delay_ms(600);
lcd_gotoxy(2,2);
      printf(lcd_putc,"vin=%f V",volt2);
       delay_us(200);//delay for reading and displaying the value on the screen(LCD)
   }
}

volt2=(volt1*30.0)/1023.0;