C language

Implement a function with the following prototype: char* findAllDigits(char* str); This function scans the input string and returns its digital characters as one string. For example, when the input is "April 28th, 11am", this function returns "2811"; when there is no digital character, it returns NULL Extra credit: Based on the function of problem 4, develop one function with the following prototype: char* findsimilarchar(char* str, int type); The second parameter type specifies the category of character to be returned