checking a string for correct characters in c
c, string
Solution
You want the standard library function `strspn`:
strspn(str, " *(12axb") == strlen(str);
It will count characters in `str` until it sees the first one that isn't one of the characters in the second argument. Thus, if it doesn't find any non-matching characters, it will return the length of the string.
A faster way to write the same, though perhaps less clear, is to check for `\0` instead of calling `strlen`:
str[strspn(str, " *(12axb")] == '\0';
Problem
Is there any easier way to do the following in c? ``` unsigned short check_str(char *str) { while (*str) { if (!(*str == ' ' || *str == '(' || *str == ')' || *str == '1' || *str == '2' || *str == 'a' || *str == 'x' || *str == 'b')) return 0; str++; } return 1; } ``` basically it checks a string for any characters other then the ones listed and returns false if it finds one. is there a more simple function?