function
<cstring>

strcspn

size_t strcspn ( const char * str1, const char * str2 );
Get span until character in string
Scans str1 for the first occurrence of any of the characters that are part of str2, returning the number of characters of str1 read before this first occurrence.

The search includes the terminating null-characters. Therefore, the function will return the length of str1 if none of the characters of str2 are found in str1.

Parameters

str1
C string to be scanned.
str2
C string containing the characters to match.

Return value

The length of the initial part of str1 not containing any of the characters that are part of str2.
This is the length of str1 if none of the characters in str2 are found in str1.
size_t is an unsigned integral type.

Example

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/* strcspn example */
#include <stdio.h>
#include <string.h>

int main ()
{
  char str[] = "fcba73";
  char keys[] = "1234567890";
  int i;
  i = strcspn (str,keys);
  printf ("The first number in str is at position %d.\n",i+1);
  return 0;
}


Output:

The first number in str is at position 5

See also

strpbrk
Locate characters in string (function )
strspn
Get span of character set in string (function )
strstr
Locate substring (function )
strncmp
Compare characters of two strings (function )

C++