Pointers basics help!

Using Arduino Programming Questions
#1

Hi possibly a very noobish question so apologies.

I am making a simple program to teach myself how pointers work.

Basically, I have tried to write a program that turns on LED1 on its first loop through, then turn on LED2 on its second loop through etc using pointers.

I have written the code with the understanding that where ever I put the pointer, the program will substitute it for the variable it is currently pointing to/associated with.

int Count = 1; //a variable which increments every loop of the program
int *pointer1; //pointer which points to LED outputs
int *pointer2; //pointer which points to LED target
int LedState1 = LOW;  //LED output logic level 1
int LedState2 = LOW;  //LED output logic level 2
int LedState3 = LOW;  //LED output logic level 3
int Led1 = 5;  //Pin# with LED 1 on
int Led2 = 8;  //Pin# with LED 1 on
int Led3 = 9;  //Pin# with LED 1 on
 
void setup() {
  Serial.begin(9600);
  pinMode(Led1,OUTPUT);
  pinMode(Led2,OUTPUT);
  pinMode(Led3,OUTPUT);
}

void loop() {
   if (Count == 1)
  {
  pointer1 = &LedState1;  //so in digitalwrite at end of loop, the second half will be LedState1
  pointer2 = &Led1;  //first half of digitalwrite will be Led1
  }
  if (Count == 2)
  {
  pointer1 = &LedState2;  //second half will be substitued for LedState2
  pointer2 = &Led1;  //first half of digitalwrite will be Led2
  }
  if (Count == 3)
  {
  pointer1 = &LedState3;  //second half will be substitued for LedState3
  pointer2 = &Led1;  //first half of digitalwrite will be Led3
  }
  if (pointer1 == HIGH)  //changing LedStateN logic levels
    {
      pointer1 = LOW;
    }
  else
  {
    pointer1 = HIGH;  
  }
  digitalWrite(pointer2, pointer1)
  if (Count < 3) ++Count;
  else
  {
    Count = 1;
  }
}

With this code, I get the error message_invalid conversion from ‘int’ to ‘int*’ [-fpermissive]_ on the line “pointer1 = HIGH”.

I would have thought this would have worked, because if variable Count = 1 > then pointer1 points to variable LedState1 > then that line which is has been highlighted as wrong would read LedState1 = HIGH… which makes sense? Where am I going wrong?

#2

DSAFS2016:
Where am I going wrong?

int *pointer1;;  // pointer1 is a POINTER

how do you expect this to work, then?

if (pointer1 == HIGH) // pointers don't have states of high or low

dereference the pointer to get its value:

if (*pointer1 == HIGH)// if (what's pointed to by pointer1 == HIGH)
#3

Thanks for your help BulldogLowell,

That made the program work!

#4

A couple of links you might want to check out - search for "pointer cheat sheet"

I can't find the original sheet I used to have (and now I need it too!!), but this should help. There seem to be two types of people out there - those that pointers are "intuitively obvious no matter how complicated they are" and the rest of us that struggle with the silly things :o

#5