std::string::find_first_not_of in C++
It searches the string for the first character that does not match any of the characters specified in its arguments. Here we will describe all syntaxes it holds.
Return value : Index of first unmatched character when successful or string::npos if no such character found.
Syntax 1: Search for the first character that is not an element of the string str.
size_type string::find_first_not_of (const string& str) const
str : Another string with the set of characters
to be used in the search.
#include <iostream>
using namespace std;
void find_first_not_ofDemo(string str1, string str2)
{
string::size_type ch = str1.find_first_not_of(str2);
cout << "First unmatched character : " ;
cout << str1[ch];
}
int main()
{
string str1( "Hello World!" );
string str2( "GeeksforGeeks" );
cout << "Original String : " << str1 << endl;
cout << "String to be looked in : " << str2 << endl;
find_first_not_ofDemo(str1, str2);
return 0;
}
|
Output:
Original String : Hello World!
String to be looked in : GeeksforGeeks
First unmatched character : H
Syntax 2: Search for the first character from index idx that is not an element of the string str.
size_type string::find_first_not_of (const string& str, size_type idx) const
str : Another string with the set of characters
to be used in the search.
idx : is the index number from where we have to
start finding first unmatched character.
#include <iostream>
using namespace std;
void find_first_not_ofDemo(string str1, string str2)
{
string::size_type ch = str1.find_first_not_of(str2, 3);
cout << "First unmatched character : " ;
cout << str1[ch];
}
int main()
{
string str1( "geeKsforgeeks" );
string str2( "GeeksforGeeks" );
cout << "Original String : " << str1 << endl;
cout << "String to be looked in : " << str2 << endl;
find_first_not_ofDemo(str1, str2);
return 0;
}
|
Output:
Original String : geeKsforgeeks
String to be looked in : GeeksforGeeks
First unmatched character : K
Syntax 3: Searches for the first character that is or is not also an element of the C-string cstr.
size_type string::find_first_not_of (const char* cstr) const
cstr : Another C-string with the set of characters
to be used in the search.
Note that cstr may not be a null pointer (NULL).
#include <iostream>
using namespace std;
void find_first_not_ofDemo(string str)
{
string::size_type ch = str.find_first_not_of( "geeksforgeeks" );
cout << "First unmatched character : " ;
cout << str[ch];
}
int main()
{
string str( "GeeksforGeeks" );
cout << "Original String : " << str << endl;
find_first_not_ofDemo(str);
return 0;
}
|
Output:
Original String : GeeksforGeeks
First unmatched character : G
Syntax 4: Search for the first character from index idx that is not an element of the C-string cstr
size_type string:: find_first_not_of (const char* cstr, size_type idx) const
cstr : Another string with the set of characters
to be used in the search.
idx : is the index number from where we have to
start finding first unmatched character.
Note that cstr may not be a null pointer (NULL).
#include <iostream>
using namespace std;
void find_first_not_ofDemo(string str)
{
string::size_type ch = str.find_first_not_of( "geeksForgeeks" , 5);
cout << "First unmatched character : " ;
cout << str[ch];
}
int main()
{
string str( "GeeksforGeeks" );
cout << "Original String : " << str << endl;
find_first_not_ofDemo(str);
return 0;
}
|
Output:
Original String : GeeksforGeeks
First unmatched character : f
Syntax 5: Finds first character in str which is not equal to char c.
size_type string::find_first_not_of (char c) const
c Character c with which contents of str are required to be compared.
#include <iostream>
using namespace std;
void find_first_not_ofDemo(string str)
{
string::size_type ch = str.find_first_not_of( 'G' );
cout << "First unmatched character : " ;
cout << str[ch];
}
int main()
{
string str( "GeeksforGeeks" );
cout << "Original String : " << str << endl;
find_first_not_ofDemo(str);
return 0;
}
|
Output:
Original String : GeeksforGeeks
First unmatched character : e
Syntax 6: Finds first character in str from index idx which is not equal to char c.
size_type string::find_first_not_of (char c, size_type idx) const
c : Character c with which contents of str
are required to be compared.
idx : index from where search of the first
unmatched character is to be started
#include <iostream>
using namespace std;
void find_first_not_ofDemo(string str)
{
string::size_type ch = str.find_first_not_of( 'G' , 6);
cout << "First unmatched character : " ;
cout << str[ch];
}
int main()
{
string str( "GeeksforGeeks" );
cout << "Original String : " << str << endl;
find_first_not_ofDemo(str);
return 0;
}
|
Output:
Original String : GeeksforGeeks
First unmatched character : o
Syntax 7: Search for the first character that is also not an element of the chars_len characters of the character array chars, starting at index idx.
size_type string::find_first_not_of
(const char* chars, size_type idx, size_type chars_len) const
*chars : is the character array with which
searching of first unmatched is to be performed.
idx : index number in string
chars_len : is the character length in
*chars to be picked for searching purpose
#include <iostream>
using namespace std;
void find_first_not_ofDemo(string str)
{
string::size_type ch = str.find_first_not_of( "svmnist" , 4, 3);
cout << "First unmatched character : " ;
cout << str[ch];
}
int main()
{
string str( "GeeksforGeeks" );
cout << "Original String : " << str << endl;
find_first_not_ofDemo(str);
return 0;
}
|
Output:
Original String : GeeksforGeeks
First unmatched character : f
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Last Updated :
11 Jul, 2017
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