Code:I have a program that takes in a string of less than 80 characters from keyboard. AND it will convert all alphabets into UPPERCASE. But I do not know how to exclude numbers, punctuations, hyphens, spaces, symbols etc. when displaying. for the time being my program is this: #include <stdio.h> #include <ctype.h> void upstr(char *s) { char *p; for (p = s; *p != '\0'; p++) *p = (char) toupper(*p); } int main(void) { char mystring[] = "strawberry cake!"; puts(mystring); upstr(mystring); puts(mystring); return(0); } how do i exclude this punctuations and spaces??? i need HELP!!!