a)Write a C function countDigits() that takes a string as parameter, finds and returns the number of numeric characters ('0', '1', ... '9') in the string. Prototype: int countDigits(char str[]);

Write a C function shrinkSpace() that takes a string as parameter, replaces the goups of whitespace character by a single space. Example: " Abcd 7 24 open " " Abcd 7 24 open " Prototype: void shrinkSpace(char str[]);

Write a C function strShuffle() that takes two strings (say s1, s2) as parameters, stores into s2 first the even indexed characters of s1 then the odd indexed characters of s1. Example: if s1 is "Abcd1234", the function will make s2 as "Ac13bd24" Prototype: void strShuffle(char s1[], char s2[]);