String manupulation

1. Reverse a string by preserving its position. 
I/p: Hi Welcome O/p: iH emocleW

2.Remove duplicates from string/array/list

3.Longest substring without repeating character.
I/p:geeksforgeeks O/p:eksforg

4.Find if two strings/numbers are palindrome/not

5.Find if two strings/numbers are anagram/not

6.Sort an array/list/string

7.Count occurrence of characters in a string. 
I/p: hello World O/p: h-1,e-1,l-3,o-2,w-1,r-1,d-1

8.Print the duplicate character in a string. 
I/p: hello World O/p: l,o

9.Print only special characters in a string. 
I/p: hello@34%Wo$rld O/p:@%$

10.Reverse the given string. 
I/p: hello World O/p: World Hello

11.Print the difference between two strings. 
I/p: Str1="Have a nice day" str2="Have a good day" O/p: nice, good

12. Count the words in given String
 I/p: It is a good day O/p:5

13.Second highest element in an array
 I/p: {5,2,7,1,4,9} O/p: 7

14.Find common elements of 2 array
 I/p: a1={1,2,3,4,5} a2={4,5,6,7,8} O/p: {4,5}

15. I/p: a2b3c1 O/p:aabbbc

16.Find if given number is prime/not
 I/p: 3 O/p:prime

17. Fibonacci series
 I/p: count-5 O/p: 0 1 1 2 3

18. Factorial of a number
 I/p: 5 O/p:120

19.Find minimum and maximum element in an array
 I/p: a1={2,5,8,3,1} O/p: min-1 max-8

20.Find the max repeated word in a sentence
I/p: str1="This is a test.This test is only a test" O/p: test