problem in displaying ADC value on LCD 16*2 using ATMEGA32 in c code

#include <avr/io.h> 
#define F_CPU 8000000
#include<util/delay.h>

#define LCD_DATA PORTC 	// LCD data port
#define ctrl PORTA
#define en PA6 			// enable signal
#define rw PA5 			// read/write signal
#define rs PA4 			// register select signal

void LCD_cmd(unsigned char cmd);
void LCD_init(void);							// initialization of LCD
void LCD_write_data(unsigned int data);				//Single Character Display
void LCD_send_string(char *string);				//Character Array Display
void ADC_init(void);							//initialization of ADC
unsigned int ADC_StartConversion(unsigned int channel);//function of ADC
void LCD_read_data(unsigned int data);

int main(void) 
{
   
    unsigned int adc_result,adc_ppm;
	
	DDRC=0xFF;				// Port C as output port
	DDRB=0xFF;				// Port B as output port
	
	DDRA=(1<<PA6)|(1<<PA5)|(1<<PA4); 		// making PORTA pins 4,5,6 as output for LCD

	PORTC=0x00;				// Clearing Port C
    
	
	MCUCSR|=(1<<JTD);		// sending 1 to JTD to disable JTAG interface with Port C
	MCUCSR|=(1<<JTD);		
	
	ADC_init();				//initialization of ADC
	_delay_ms(10);
	LCD_init(); 			// initialization of LCD
	_delay_ms(2); 			// delay of 1 milli seconds


	LCD_cmd(0x80);					//cursor on the 1st line
	_delay_ms(2);
	LCD_send_string("CO Level:"); 	// Display "CO level" on first line
	_delay_ms(2);	

	while (1)
	{
		adc_result=ADC_StartConversion(0);  //Get the adc value of channel zero 
		adc_ppm=(adc_result/20);        	/*since 1ppm=20counts the adc_result is divided by 20 
											inorder to get the CO ppm Value*/
	
		LCD_cmd(0x89); 						//cursor on 1st line 10th position                              
		_delay_ms(10);
		LCD_write_data(adc_ppm);	         	//sending ppm value to LCD
	
		LCD_cmd(0x8C);					 	//cursor on 1st line 13th position
		_delay_ms(2);
		LCD_send_string("PPM");     	 //Displaying PPM "the unit" of gas to LCD
		
				
		if(adc_ppm<=20)
		{
			LCD_cmd(0xC7);				//cursor on the 2nd line 7th position
			_delay_ms(2);
			LCD_send_string("  SAFE ");	//displays SAFE when ppm value is <20
			PORTB=0x00;
   			_delay_ms(500);
   			PORTB=0x01;
   			_delay_ms(500); 
    	}


		else if(adc_ppm>20)
	 	{
			LCD_cmd(0xC6);				//cursor on the 2nd line 6th position
			_delay_ms(2);
	    	LCD_send_string(" DANGER ");	//displays DANGER when ppm value is >20
			PORTB=0x00;
   			_delay_ms(500);
   			PORTB=0x02;
   			_delay_ms(500);
	     }

}

	return 0;

}

void LCD_send_string(char *string)								//Character Array Display
{
 	while(*string)
		{
	 		LCD_DATA= *string;
	 		ctrl = (1<<rs)|(0<<rw)|(1<<en); // RW as LOW and RS, EN as HIGH
		 	_delay_ms(2);
	 		ctrl = (1<<rs)|(0<<rw)|(0<<en); // EN and RW as LOW and RS HIGH
	 		_delay_ms(2); 					// delay to get things executed
			string++;
		}
}


void LCD_init(void)	 							// initialization of 16X2 LCD in 8bit mode
{
	LCD_cmd(0x38);
	_delay_ms(2);
 
	LCD_cmd(0x01); 		// Clear Display, Cursor to Home
	_delay_ms(2);	
 
	LCD_cmd(0x0E); 		// Display, Cursor, and Cursor Blink OFF
	_delay_ms(2);
 
	LCD_cmd(0x80); 		// ---8 go to first line and --0 is for 0th position
	_delay_ms(2);

return;
}
 
void LCD_cmd(unsigned char cmd)
  {
	LCD_DATA=cmd;
	ctrl =(0<<rs)|(0<<rw)|(1<<en); // RS and RW as LOW and EN as HIGH
	_delay_ms(2);
	ctrl =(0<<rs)|(0<<rw)|(0<<en); // RS, RW , LOW and EN as LOW
	_delay_ms(2);
 
return;

}

void LCD_write_data(unsigned int data)							//Single Character Display
{
 	
	LCD_DATA= data;
	ctrl = (1<<rs)|(0<<rw)|(1<<en); // RW as LOW and RS, EN as HIGH
	_delay_ms(2);
	ctrl = (1<<rs)|(0<<rw)|(0<<en); // EN and RW as LOW and RS HIGH
	_delay_ms(2);					// delay to get things execute
	
 return;
}
void LCD_read_data(unsigned int data)							//Single Character Display
{
 	
	LCD_DATA= data;
	ctrl = (1<<rs)|(1<<rw)|(1<<en); // RW as LOW and RS, EN as HIGH
	_delay_ms(2);
	ctrl = (1<<rs)|(1<<rw)|(0<<en); // EN and RW as LOW and RS HIGH
	_delay_ms(2);					// delay to get things execute
	
 return;
}

void ADC_init()												//initialization of ADC
 {
   ADCSRA=0x82; 	//Enable ADC , sampling freq=osc_freq/64
   _delay_ms(10);
   ADMUX=0x40; 		//Result right justified, select channel zero
 }

unsigned int ADC_StartConversion(unsigned int channel)
{
   
   ADMUX=channel; 					//Select a channel
   _delay_ms(10);   					//Wait till the channel is selected
   
   ADCSRA|=(1<<ADSC);   					//Start the ADC conversion by setting bits for ADEN, ADSC, Prescaler to /64 
   
while((ADCSRA & (1<<ADIF))==0);  	//Wait till the conversion is over
  
                               	//ADIF will be set once ADC conversion is complete	
return(ADC);               		 //Return the 10-bit result
}

void ADC_init()												//initialization of ADC
         {
           ADCSRA=0x82; 	//Enable ADC , sampling freq=osc_freq/64
           _delay_ms(10);
           [B]ADMUX=0x40; 		//Result right justified, select channel zero[/B]
         }

unsigned int ADC_StartConversion(unsigned int channel)
        {
           
           [COLOR="#FF0000"]ADMUX=channel; 					//Select a channel[/COLOR]
           _delay_ms(10);   					//Wait till the channel is selected
           
           ADCSRA|=(1<<ADSC);   					//Start the ADC conversion by setting bits for ADEN, ADSC, Prescaler to /64 
           
        while((ADCSRA & (1<<ADIF))==0);  	//Wait till the conversion is over
          
                                       	//ADIF will be set once ADC conversion is complete	
        return(ADC);               		 //Return the 10-bit result
        }