Search string for occurrence of character set

#include <string.h>
#include <stdio.h>

int main(void)
{
  int len;

  len = strcspn("this is a test", "ab");
  printf("%d", len);

  return 0;
}

1.	Look up names in a hardcoded list
2.	Finding occurrences of one string in another: strstr
3.	A demonstration of seeking and finding
4.	Find sub string: our own function
5.	Search a char inside a string
6.	Scan string for specified characters
7.	Find last occurrence of character in string
8.	Find substring
9.	Search string
10.	Search string for occurrence of character set: how to use strcspn
11.	Scan string for specified characters: how to use strpbrk
12.	Find last occurrence of character in string: how to use strrchr
13.	Find substring: how to use strstr
14.	Find character in string: how to use strchr

Search string for occurrence of character set : String Search « String « C / ANSI-C