#include <avr/io.h>
#define F_CPU		16000000UL
#include <util/delay.h>
 
#define CDS_10		341
#define CDS_20		450
#define CDS_50		550
#define CDS_80		650
#define CDS_100		731
 
void init_adc();
unsigned short read_adc();
void show_adc_led(unsigned short data);
 
int main()
{
	unsigned short value;
	DDRA = 0xff;
	DDRF = 0x00;
	init_adc();
	while(1)
	{
		value = read_adc();
		show_adc_led(value);
	}
}
 
void init_adc();
unsigned short read_adc();
void show_adc_buzzer(unsigned short data);
 
int main()
{
	unsigned short value;
	DDRB |= 0x10;
	DDRF = 0x00;
	init_adc();
	while(1)
	{
		value = read_adc();
		show_adc_buzzer(value);	
	}
}
 
void init_adc()
{
	ADMUX = 0x40;
	ADCSRA = 0x87;
}
 
unsigned short read_adc()
{
	unsigned char adc_low, adc_high;
	unsigned short value;
	ADCSRA |= 0x40;
	while((ADCSRA & 0x10) != 0x10)
				;
	adc_low = ADCL;
	adc_high = ADCH;
	value = (adc_high << 8) | adc_low;
	
	return value;			
}
 
 
void show_adc_led(unsigned short value)
{
	if(value <= CDS_10)			PORTA = 0xff;
	else if(value <= CDS_20)	PORTA = 0x77;
	else if(value <= CDS_50)	PORTA = 0x55;
	else if(value <= CDS_80)	PORTA = 0x11;
	else if(value <= CDS_100)	PORTA = 0x01;
	else                        PORTA = 0x00;
}
 
컴파일후에 자꾸 오류가 뜨네요
Description                                                   Project                        File                Line
recipe for target 'main.o' failed                     GccApplication13       Makefile         76 
! previous definition of 'main' was here        GccApplication13       main.c            15
redefinition of 'main'                                     GCCApplication13     main.c             32
 
광센서를 가리면 led가 켜지며 버저에서 삐소리가 나게 만드는 코드를 작성중인데 
어디 부분이 잘못됬는지 잘 모르겠습니다 ㅠㅠ 
잘못된 부분이있다면 수정 부탁드리겠습니다!!