Step by Step solution about How to resolve the algorithm Determine if a string has all the same characters step by step in the Julia programming language

Source Code Explanation:

The provided Julia code performs the following tasks:

1. firstdifferent Function:

• This function takes a string s as input and returns the index of the first character in the string that is different from the first character of the string.
• If all characters in the string are the same, it returns nothing.
• The function uses the findfirst function to find the index of the first occurrence of a character that does not match the first character of the string.

2. testfunction Function:

• This function takes a list of strings strings as input and prints a table showing the following information for each string:
  • String: The original string.
  • Length: The length of the string.
  • All Same: Indicates if all characters in the string are the same.
  • First Different (Hex): The hexadecimal representation of the first different character, if it exists.
  • Position: The position of the first different character in the string, if it exists.

3. Main Execution:

• The testfunction is called with a list of strings as input.
• The function iterates through each string in the list, calculates the first different character and its position, and prints the results in a table.

Example Output:

String                  | Length | All Same | First Different(Hex) | Position
-----------------------------------------------------------------------------
                      |     0 | yes      | nothing              | 0

| | 1 | yes | nothing | 0 | | 1 | yes | nothing | 0 | | 3 | no | 5 | 1 | | 4 | no | . | 1 | | 5 | no | T | 2 | | 9 | no | k | 5 | | 5 | no | é | 2 | | 5 | no | 🐺 | 3 | | 4 | no | 🎄 | 2

Explanation of Example Output:

• For the empty string, all characters are the same (none), so the "All Same" column is "yes" and the "First Different" column is "nothing".
• For the string " ", all characters are the same (space), so the "All Same" column is "yes" and the "First Different" column is "nothing".
• For the string "2", all characters are the same (2), so the "All Same" column is "yes" and the "First Different" column is "nothing".
• For the string "333", all characters are the same (3), so the "All Same" column is "yes" and the "First Different" column is "nothing".
• For the string ".55", the first different character is '.', represented in hex as 0x2e, and its position is 1, so the "First Different" column is "2e (0x2e)".
• For the string "tttTTT", the first different character is 'T', represented in hex as 0x54, and its position is 2, so the "First Different" column is "54 (0x54)".
• For the string "4444 444k", the first different character is 'k', represented in hex as 0x6b, and its position is 5, so the "First Different" column is "6b (0x6b)".
• For the string "pépé", the first different character is 'é', represented in hex as 0xe9, and its position is 2, so the "First Different" column is "e9 (0xe9)".
• For the string "🐶🐶🐺🐶", the first different character is '🐺', represented in hex as 0x1f43a, and its position is 3, so the "First Different" column is "1f43a (0x1f43a)".
• For the string "🎄🎄🎄🎄", the first different character is '🎄', represented in hex as 0x1f384, and its position is 2, so the "First Different" column is "1f384 (0x1f384)".

firstdifferent(s) = isempty(s) ? nothing : findfirst(x -> x != s[1], s)

function testfunction(strings)
   println("String                  | Length | All Same | First Different(Hex) | Position\n" *
           "-----------------------------------------------------------------------------")
    for s in strings
        n = firstdifferent(s)
        println(rpad(s, 27), rpad(length(s), 9), n == nothing ? "yes" :
            rpad("no               $(s[n])   ($(string(Int(s[n]), base=16)))", 36) * string(n))
    end
end

testfunction([
	"",
	"   ",
	"2",
	"333",
    ".55",
    "tttTTT",
    "4444 444k",
    "pépé",
    "🐶🐶🐺🐶",
    "🎄🎄🎄🎄",
])