cmd first_unique_char

#!/bin/bash
# ---------------------------------------------------------
# Program: Find First Non-Repeating Character in a String
# File Name: first_unique_char.sh
# Description:
#   This script reads a string from the user and uses
#   nested loops to find the first character that appears
#   only once in the string.
# ---------------------------------------------------------

# Prompt user to enter a string
read -p "Enter a string: " str

# Get length of the string
len=${#str}

# Variable to track if a unique character is found
found=0

# Outer loop: iterate through each character in the string
for (( i=0; i<$len; i++ ))
do
    # Initialize count for each character
    count=0

    # Extract the current character at position i
    char=${str:i:1}

    # Skip checking if the character is a space
    if [[ "$char" == " " ]]; then
        continue
    fi

    # Inner loop: compare the selected character with all others
    for (( j=0; j<$len; j++ ))
    do
        # If characters match, increase the count
        if [[ ${str:j:1} == $char ]]; then
            ((count++))
        fi
    done

    # If count is 1, it means this character is unique
    if [[ $count -eq 1 ]]; then
        echo "First non-repeating character: $char"
        found=1
        break
    fi
done

# If no unique character is found after the loops
if [[ $found -eq 0 ]]; then
    echo "No non-repeating character found."
fi