C++ String Library - find_first_not_of

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Description

It searches the string for the first character that does not match any of the characters specified in its arguments.

Declaration

Following is the declaration for std::string::find_first_not_of.

size_t find_first_not_of (const string& str, size_t pos = 0) const;

C++11

size_t find_first_not_of (const string& str, size_t pos = 0) const noexcept;

C++14

size_t find_first_not_of (const string& str, size_t pos = 0) const noexcept;

Parameters

• str − It is a string object.

• len − It is used to copy the characters.

• pos − Position of the first character to be copied.

Return Value

none

Exceptions

if an exception is thrown, there are no changes in the string.

Example

In below example for std::string::find_first_not_of.

#include <iostream>
#include <string>
#include <cstddef>

int main () {
   std::string str ("It looks for non-alphabetic characters...");

   std::size_t found = str.find_first_not_of("abcdefghijklmnopqrstuvwxyz ");

   if (found!=std::string::npos) {
      std::cout << "The first non-alphabetic character is " << str[found];
      std::cout << " at position " << found << '\n';
   }

   return 0;
}

The sample output should be like this −

The first non-alphabetic character is I at position 0