how to give a parameters to a function in C [closed] - c

Question

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I don't know how to give a parameters to a function. I wrote a body, as you can see in my program below. Any answers and explanations appreciated!
#include <avr/io.h>
#include <stdint.h>
// Ceramic Resonator
#ifndef F_CPU
#define F_CPU 3686400 // 4MHz
#endif
// UART
#define UART_BAUD_RATE 9600
#define UART_BAUD_CALC(UART_BAUD_RATE,F_OSC) ((F_CPU)/((UART_BAUD_RATE)*16L)-1)
int decode( int rcv[i], ... ){ !!!
int returnValue;
if ((rcv[0] == rcv[1]) && (rcv[0] == rcv[2]) && (rcv[1] == rcv[2])){
returnValue = 0;
//return UDR0;
}
else if (rcv[1] != rcv[2] && (rcv[0] == rcv[1])){
returnValue = 1;
//UDR0 = 01;
}
else if (rcv[1] != rcv[2] && (rcv[0] == rcv[2])){
returnValue = 2;
//UDR0 = 02;
}
else if (rcv[0] != rcv[1] && (rcv[1] == rcv[2])){
returnValue = 3;
//UDR0 = 03;
}
return returnValue;
}
int main(void){
// USART
UBRR0H =(uint8_t) (UART_BAUD_CALC(UART_BAUD_RATE,F_CPU) >>8);
UBRR0L =(uint8_t) UART_BAUD_CALC(UART_BAUD_RATE,F_CPU);
UCSR0B = (1<<RXEN0) | (1<<TXEN0); // enable receiver and transmitter,
UCSR0C = (3<<UCSZ00); // 8 bit (default: asynchronous, no parity, 1 stop-bit)
DDRC = (1<<5); // set data direction register bit 5 to one, this means PC5 is configured as output
PORTC = (1<<5); // set output value of PC5 to High-Level (Source Current, 5V to ground)
// VARIABLES
//uint8_t get;
// PROGRAM
unsigned char code[3] = {'x','y','z'}; // Here you need to write your code
unsigned char rcv[3]={'0','0','0'}; // received data
int i = 0;
int retVal;
while(1){
i = 0;
for(i=0;i<=2;i++){
// wait for empty transmit buffer
//while (!(UCSR0A & (1<<UDRE0)));
// wait for data to be received
while (!(UCSR0A & (1<<RXC0)));
/* put data into buffer, sends the data*/
{
code[i]= UDR0 ;
}
//while(1) // forever
//{
PORTC ^= (1<<5); //this is for LED
// get received data from buffer
rcv[i] = code[i];
}
retVal = decode(int rcv[i], ... ); !!!
// wait for empty transmit buffer
while (!(UCSR0A & (1<<UDRE0)));
// put data into buffer, sends the data
/*if ((rcv[0] == rcv[1]) && (rcv[0] == rcv[2]) && (rcv[1] == rcv[2]))*/
UDR0 = retVal;
}
}

Answer 1

I like #Ari's answer but I feel like I should add that you can use variable parameter lists if that's what you want. You can find a good tutorial here, but this would probably be more work that you require.
Edit:
I just noticed the // Ceramic resonator comment so I'm guessing you're in an Embedded environment in which case I would strongly recommend a simple pointer like #Ari suggested. The variable parameter list might not be fully implemented on your architecture.

Answer 2

You should put pointer to an array and maybe size of it:
change:
int decode( int rcv[i], ...)
to
int decode( unsigned char* rcv)
and
retVal = decode(int rcv[i], ... ); !!!
to
retVal = decode(rcv); //rcv is a pointer