aruindo to read my xbee accelerometer data

Just a quick run down on statements,

int a = 4;

if( a > 3 )
  a++;  //Only this line is part of the above if
  a++; //This will run weather or not the if does anything.

if( a > 4 ){
    a++;  //Both these are part of the same if
    a++;
}


for( int b = 0 ; b < 5 ; ++b );
  a++; //Due to semicolon on for statement, this a++ is not part of it and will only run once when the loop is finished.

for( int b = 0 ; b < 5 ; ++b )
  a++; //This is part of the loop
  a++; //This is not

for( int b = 0 ; b < 5 ; ++b ){
  a++; //These two instructions are part of the loop
  a++; 
}

//This is completely wrong
    byte[(12)*256]+(13)]  = Serial.read( ,x);
    byte[(14)*256]+(15)]  = Serial.read( ,y);
    byte [(16)*256]+(17)] =Serial.read(  ,z);

the '[' and ']' brackets dont match, and byte is a data type, not a variable.

Serial.read( ,x);
Functions cannot have empty paramaters. ( Serial.read doesn't take any paramaters ).

Read this: http://www.cplusplus.com/doc/tutorial/