how to give a parameters to a function in C -

i don't know how give parameters function. wrote body, can see in program below. answers , 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 , transmitter,         ucsr0c = (3<<ucsz00); // 8 bit (default: asynchronous, no parity, 1 stop-bit)          ddrc = (1<<5); // set data direction register bit 5 one, means pc5 configured output         portc = (1<<5); // set output value of pc5 high-level (source current, 5v ground)         // variables         //uint8_t get;         // program          unsigned char code[3] = {'x','y','z'}; // here need write code         unsigned char rcv[3]={'0','0','0'}; // received data          int = 0;          int retval;          while(1){             = 0;             for(i=0;i<=2;i++){                 // wait empty transmit buffer                  //while (!(ucsr0a & (1<<udre0)));                 // wait data received                 while (!(ucsr0a & (1<<rxc0)));                 /* put data buffer, sends data*/                 {                       code[i]= udr0  ;                 }                  //while(1) // forever                 //{                   portc ^= (1<<5); //this led                  // received data buffer                 rcv[i] = code[i];               }             retval = decode(int rcv[i], ... ); !!!             // wait empty transmit buffer             while (!(ucsr0a & (1<<udre0)));             // put data buffer, sends data             /*if ((rcv[0] == rcv[1]) && (rcv[0] == rcv[2]) && (rcv[1] == rcv[2]))*/             udr0 = retval;                      }      } 

you should put pointer array , 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 pointer