C string utility functions Implement the following functions which are equivalent to strlen, strcat and strcpy functions in : (DON'T include library in your source file) By passing the pointer of a string array, the function returns the size of the string array: int count_char(const char* str); 2. By passing the pointers of two string arrays, the content of the source string array will be appended to the end of the destination string array: char* concatenate(char * destination, const char * source); 3. By passing the pointers of two string arrays, the content of the source string array will be copied to the destination string array: char* copy(char * destination, const char * source); Test all functions in the main(), prompt for the user input and save into two C strings. Print out the size of each string, concatenate the second string into the first string, then copy the first string to the second string Print out the content and size of both strings after invoking the concatenate and copy functions.