Using a function Multiple Times

Hello all,

If i want to call a function from an if statement, how do i do this ?
I currently write the same code over and over and use heaps of timers to delay the turning on of a relay, The time never changes.
I have yet to use functions in my programs and now i am suffering bloating badly. Please help me

if(b = 10)
{
   //  How do i tell it to do the relay function
}
void relay();
{
  digitalWrite(output, HIGH);
}
if (b == 10) {

   relay();

}
void relay();
{
  digitalWrite(output, HIGH);
}

Should be:

void relay()
{
  digitalWrite(output, HIGH);
}

Also Google "C++ tutorial".