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std::ctype::scan_is, std::ctype::do_scan_is

Defined in header <locale> 
public:
const CharT* scan_is( mask m, const CharT* beg, const CharT* end ) const;
 (1) 
protected:
virtual const CharT* do_scan_is( mask m, const CharT* beg, const CharT* end) const;
 (2)
1) public member function, calls the protected virtual member function do_scan_is of the most derived class.
2) Locates the first character in the character array [beg, end) that satisfies the classification mask m, that is, the first character c such that is(m, c) would return true.

Parameters

m - mask to search for
beg - pointer to the first character in an array of characters to search
end - one past the end pointer for the array of characters to search

Return value

Pointer to the first character in [beg, end) that satisfies the mask, or end if no such character was found.

Example

#include <locale>
#include <iostream>
#include <iterator>
 
int main()
{
    auto& f = std::use_facet<std::ctype<char>>(std::locale(""));
 
    // skip until the first letter
    char s1[] = "      \t\t\n  Test";
    const char* p1 = f.scan_is(std::ctype_base::alpha, std::begin(s1), std::end(s1));
    std::cout << "'" << p1 << "'\n";
 
    // skip until the first letter
    char s2[] = "123456789abcd";
    const char* p2 = f.scan_is(std::ctype_base::alpha, std::begin(s2), std::end(s2));
    std::cout << "'" << p2 << "'\n";
}

Output:

'Test'
'abcd'

See also

[virtual]
 locates the first character in a sequence that fails given classification
(virtual protected member function)

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