Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.

Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).

There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."

Encoding (MSB is bit 0, b is binary, g is Gray code):

if b[i-1] = 1
   g[i] = not b[i]
else
   g[i] = b[i]
Or:

g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):

b[0] = g[0]

for other bits:
b[i] = g[i] xor b[i-1]
Reference
 Converting Between Gray and Binary Codes. It includes step-by-step animations.
fn enc(b int) int {
    return b ^ b>>1
}
 
fn dec(gg int) int {
    mut b := 0
    mut g := gg
    for ; g != 0; g >>= 1 {
        b ^= g
    }
    return b
}
 
fn main() {
    println("decimal  binary   gray    decoded")
    for b := 0; b < 32; b++ {
        g := enc(b)
        d := dec(g)
        println("  ${b:2}     ${b:05b}   ${g:05b}   ${d:05b}  ${d:2}")
    }
}