Calling a function only once whenever conditions are correct

Questions & Answers
1

I have code which builds up charge while a button is held down and then I want it to execute a function only once. This is within a function called ScanInput() which is called from Update()

   while(Input.GetButton("Fire1"))// && (Time.deltaTime > nextFire))
    {
        //Add to the charge as long as the
        // user is holding the button
        chargeLevel += Time.deltaTime * chargeSpeed;
    firedMissile = false;
            firePlayer001Missile(firedMissile); 
        yield;
    }

    chargeLevel = 0.0;

Heres the code for the function firePlayer001Missile

function firePlayer001Missile(firedMissile)  
{
if(!firedMissile)
{
    var player001Missile = new Instantiate(currentMissileType, GameObject.Find("Player001ShotSpawnPoint001").transform.position,Quaternion.identity);
currentMissileType.transform.Translate(0,shootForce*Time.deltaTime,0);
player001Missile.rigidbody.AddForce(transform.up*shootForce);
bulletCount++;
firedMissile=true;
}
return firedMissile;
}

As it is now, it fires a barrage of bullets which I think is equal to the number of calls to the function firePlayer001Missile; I want it to fire only one bullet after the fire button has been held down.

2

I got this working by having a bool set to false. Then an If condition for false on the bool (and it always is false the first time the code is run), followed by the conditional code I want to run once and ending by setting the bool to true.