Program for converting decimals to binary with led output of the binary values

Using Arduino Programming Questions
#1

Hi,

I’m currently trying to code an exercise for school in which we have to convert all the numbers in the interval 0-15 to binary and display the binary value using 4 led’s (first led: 8, 2nd led: 4, …).

Now, I’m kinda stuck because it doesn’t work. I’m sure that the inner loops work correctly because I have tested these seperately. But when I add the outer loop for going through the numbers in 0-15, nothing works.

Can anybody find my mistake?

Thanks in advance!

int ledpins [] = {2, 3, 4, 5};    //pins that have a led connected

void setup() {
  for (int i = 0; i < 4; i++) {
    pinMode(ledpins[i], OUTPUT);
  }
}

void loop() {
  for (int number = 0; number < 16; number++) {    //for number from 0-15
    int var = number;
    delay(2000);
    
    for (int i = 0; i < 4; i++) {         //turn all leds off
      digitalWrite(ledpins[i], LOW);
    }
    
    int j = 0;
    for (int i = 8; i >= 1; i -= (i / 2)) {   //so i = 8, i = 4, i = 2, i = 1
      if (var >= i) {
        digitalWrite(ledpins[j], HIGH);
        var -= i;
      }
      j++;
    }
  }
  for(;;){}   //everything is only executed once

  }
#2

Just test the individual bits of the variable - the number already is binary, there is no need for a conversion.
Just use shift and bitwise AND operators.

#3

TheMemberFormerlyKnownAsAWOL:
Just test the individual bits of the variable - the number already is binary, there is no need for a conversion.

Yes, I know that it is already binary. But I'm learning to code and the exercise is made for us to learn and use for-loops, variables,...etc

#4

Ok, I found my mistake. One of the inner loops wasn't correct.
In the 2nd one, it would just go on forever as "i" would never be smaller than 1.

#5

for(;;){}  //everything is only executed onceah yeah just like while(1);

#6 
#define EVER (;;)

for EVER;
#7

TheMemberFormerlyKnownAsAWOL:

#define EVER (;;)

for EVER;

LOL !

#8