Example 1:  
Input: takeUforward  
Output: t  
Explanation: Character 't' is the left-most non-repeating character or the first non-repeating character in the string "takeUforward".

Example 2:  
Input: Engineer  
Output: g  
Explanation: Character 'g' is the left-most non-repeating character or the first non-repeating character in the string "Engineer".

Disclaimer: It's highly recommend trying to solve it before looking at the solution.

Brute Force

Algorithm

Select the first character of the string and compare it with every other character in the string.
If the current character does not match with any of the subsequent characters, immediately return or print that character as the first non-repeating character.
If the current character matches any subsequent character, move to the next character and repeat the comparison process.
If all the characters are traversed and no non-repeating character is found, return or print -1.
Return the answer, which could be either the first non-repeating character or -1 if none is found.

Code