read analog sensor with arduino uno and programming C

Using Arduino Interfacing w/ Software on the Computer
4

if I change with this one

on arduino:

int inbyte = 0;
void setup()  {
  Serial.begin(9600);
}

void loop()  {
  inbyte = Serial.read();
  
  if(inbyte=='0'){
    Serial.print(analogRead(0)); 
    delay(10);
    Serial.print(" ");
    delay(10); }
  
  if(inbyte=='1'){
    Serial.print(analogRead(1));  
    delay(10);
    Serial.print(" ");
    delay(10);}
}

on C:

while(1){
        open_port();
        
        write(fd,"0",1);
        read(fd,buf0,10);
        printf(" %s \n",buf0);
        usleep(100);
        
        write(fd,"1",1);
        read(fd,buf1,10);
        printf(" %s \n",buf1);
        usleep(100);
}

There are no result on C, but when I open the serial port monitor on arduino. The results appear on the C program.

but the result is weird.

I Put 0 in input 0 and put 5 v (1023) in input 1.
in serial monitor appear 102 0
in c appears
3
(empty)

sometimes
in serial monitor 10 0
in c appears
23
(emty)