How to allow my C++ code to update variables? - c++

Question

I'm new to coding and C++.
The code below is meant to monitor a magswitch and a status led on another controller. The code needs to run once the magswitch pin goes high (this works).
The additional code for pulseIn, is what I hope to use to monitor different flash rates of the led when I get the code working. For now I'm just looking for the state variable to update with the if and else if statements.
When I toggle the statusPin, the code picks up the changing state, but I cannot get it to update the "state" and "statuspinstate" variables.
The statuspinstate variable shows as 1, even though it is initialized as 0.
I inserted all the serial prints to try and see where things are going wrong.
This is the serial print when "statusPin" is LOW:
statuspinstate: 0
rate1: 2147483647
period: 0.00
rate2: 0
ontime: 0
offtime: 0
state: 0
statepinstatus: 1
This is the serial print when "statusPin" is HIGH
statuspinstate: 1
rate1: 2147483647
period: 0.00
rate2: 0
ontime: 0
offtime: 0
state: 0
statepinstatus: 1
Code:
const int statusPin = 19; //Reads status led
const int magSwitch = 22; //Magswitch to detect movement
int ontime,offtime,rate1,rate2;
float freq,period;
volatile unsigned int state =0;
volatile unsigned int statuspinstate = 0;
void setup()
{
pinMode(statusPin, INPUT); //input from controller
pinMode(magSwitch, INPUT);
Serial.begin(115200);
}
void loop()
{
while (digitalRead(magSwitch) == LOW) {
}
{
statuspinstate = digitalRead(statusPin);
ontime = pulseIn(statusPin,HIGH);
offtime = pulseIn(statusPin,LOW);
period = ontime+offtime;
rate1 = (ontime/period); //future use
rate2 = (offtime); //future use
Serial.println(String("statuspinstate ") + (digitalRead(statusPin))); //all serial print is debug info
Serial.println(String("rate1: ") + (rate1));
Serial.println(String("period: ") + (period));
Serial.println(String("rate2: ") + (rate2));
Serial.println(String("ontime: ") + (ontime));
Serial.println(String("offtime: ") + (offtime));
delay(500);
}
if ((ontime) != 0)
state = period;
else if (statuspinstate = 1)
state = 9999;
else if (statuspinstate = 0);
state = 0;
Serial.println(String("state: ") + (state));
Serial.println(String("statepinstatus: ") + (statuspinstate));
statuspinstate = 0; //return statuspinstate to zero
}

Answer 1

Look at your conditional, with proper indentation (do get a text editor that can indent your code for you):
if ((ontime) != 0)
state = period;
else if (statuspinstate = 1)
state = 9999;
else if (statuspinstate = 0);
state = 0;
We know that ontime is zero, so the second condition is tried next.
Now, statuspinstate = 1 is an assignment, not a comparison, and its value is "truth-y" so you take that branch.
Next, the stray semicolon in if (statuspinstate = 0); (which is also an assignment condition, but not evaluated) makes state = 0 unconditional.
So every time ontime is zero, you end up executing statuspinstate = 1 and state = 0.
What you probably want is
if (ontime != 0)
state = period;
else if (statuspinstate == 1)
state = 9999;
else if (statuspinstate == 0)
state = 0;