Why no ~ on digital 4 pin?

Using Arduino IDE 1.x
1

Why does the digital 4 pin have no ~ all the others are ~1 ~2 etc.

2

It would be unusual for any of those pins to be so-marked - which board are you talking about?

3

Arduino leonardo.
I have attached a screen shot

Untitled.jpg

4

all the others are ~1 ~2 etc.

That isn't evident in your photo.
~ denotes a PWM pin.

5

~ denotes a pin capable of pwm (analogWrite). Pin 4 does not have that capability, and hence has no ~

6

OP's picture

048a385cd5e15ae499e9ba18ba3dc450073cbfca.jpg

There's no ~ on 1 and 2 as claimed in the OP.

7

...and, Oh! Look! It also helpfully says says "PWM~"