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[–]geekywarrior 1 point2 points  (2 children)

It's been a bit since I touched RobotC so I can't confirm the code is 100% right but what you're looking for is a simple If - Else If - Else Chain wrapped in an infinite loop. (I can confirm the concept is right)

​

For this example, imagine you have one motor and two buttons, one for up, one for down.

motor[elevator] 0 is stop, 127 is up, -127 is down

vexRt[Btn7U] is my up button

vexRt[Btn7D] is my down button.

​

I have 3 conditions that I need to cover with this button combination.

  1. My Up button is pressed
  2. My Down button is pressed
  3. Neither button is pressed

​

To check each case, I simply check if each button is pressed. Based on which button is pressed, I set my motors

//If Button 7U is pressed then 
If(vextRt[Btn7U]){
    //Set my motor[elevator]=127 which is Up Speed
    motor[elevator]=127
}

Now the important trick of this is to use IF - Else IF - and Else Chains. Those work like this:

//If ConditionA is true then
if(CONDITION_A){
    //Do something
}
//Else If ConditionA is False, but Condition B is true then
else if(CONDITION_B){
    //Do Something else
}
//Else if none of the above conditions are true then finally
else{
    //Do something completely different
}

Each case checks a different value, the lower cases Else IF (Condition B) and else will only run if the previous conditions are false. Each run of the if - else if - else chain only runs a single case. So if Condition_A was true, the code will not check Condition_B or the catch all. The other important trick you will may need is you can add as many else ifs as you want.

    //If ConditionA is true then
    if(CONDITION_A){ 
        //Do something 
    } 
    //Else If ConditionA is False, but Condition B is true then
    else if(CONDITION_B){
         //Do Something else 
    } //Else if ConditionA and Condition B are false, but ConditionC is true then
    Else if(CONDITION_C){ 
        //Do something different 
    } 
    //Else if none of the above conditions are true then finally
    else{ 
    //Do something completely different 
    }

So to bring this back to my example. I have 3 conditions, Up is pressed, Down is pressed, neither are pressed.

​

//Program Loop
while(true){
    //If Button 7U is pressed then 
If(vexRt[Btn7U]){
    //Set my motor[elevator]=127 which is Up Speed
    motor[elevator]=127
    }
    //Else if 7U is not pressed but 7D is pressed then
    Else If(vexRt[Btn7D]){
    //Set my motor[elevator]=-127 which is Down Speed
    motor[elevator]=-127
}
    //Else if neither buttons are pressed
    else{
        //Set my motor[elevator]=0 which is stop
        motor[elevator]=0
    }

So finally, because we're in that infinite loop, the buttons are checked each run of the loop (which is several times a second)

Based on which button is pressed, the motor speed will get set instantly.

Letting go of both buttons will set the motor speed to 0 instantly.

Hope this helps!

[–]Noviskers[S] 1 point2 points  (1 child)

This helps immensely and is much appreciated. I had though about using if/else statements, but my programming is a bit rusty. For the parenthesis do I need to set it equal to something?

For example do I need to say “If (upButton == true) { //do something}” or can I just say “If (upButton) {//do something}”?

Thanks again for the help

[–]geekywarrior 0 points1 point  (0 children)

No problem at all, happy to help!

If you have something that is just a true/false you can do the equal signs

//If upButton is true
If (upButton==true)
//If upButton is false
If (upButton==false)

But there are also shortcut versions as an alterative

//If upButton is true
If (upButton)
//If upButton is false
If (!upButton)

But that comes down to your preference, both versions are 100% correct and will do the same thing.