From cppreference.com
constexprboolstarts_with(std::basic_string_view<CharT,Traits>sv)constnoexcept; (1) (since C++20)constexprboolstarts_with(CharTch)constnoexcept; (2) (since C++20)constexprboolstarts_with(constCharT*s)const; (3) (since C++20)Checks if the string begins with the given prefix. The prefix may be one of the following:
1) A string view sv (which may be a result of implicit conversion from another std::basic_string).
2) A single character ch.
3) A null-terminated character string s.
All three overloads effectively return std::basic_string_view<CharT,Traits>(data(),size()).starts_with(x), where x is the parameter.
Parameters
sv - a string view which may be a result of implicit conversion from another std::basic_stringch - a single character s - a null-terminated character string Return value
true if the string begins with the provided prefix, false otherwise.
Notes
macroValueStdFeature
(C++20)String prefix and suffix checking: starts_with() and ends_with()Example
Run this code
#include<cassert>#include<string>#include<string_view>intmain(){usingnamespacestd::literals;constautostr="Hello, C++20!"s;assert(""&&str.starts_with("He"sv)// (1)&&!str.starts_with("he"sv)// (1)&&str.starts_with("He"s)// (1) implicit conversion string to string_view&&!str.starts_with("he"s)// (1) implicit conversion string to string_view&&str.starts_with('H')// (2)&&!str.starts_with('h')// (2)&&str.starts_with("He")// (3)&&!str.starts_with("he")// (3));}See also
(C++20)
checks if the string ends with the given suffix
(public member function)
(C++20)
checks if the string view starts with the given prefix
(public member function of std::basic_string_view<CharT,Traits>)
(C++20)
checks if the string view ends with the given suffix
(public member function of std::basic_string_view<CharT,Traits>)
(C++23)
checks if the string contains the given substring or character
(public member function)
(C++23)
checks if the string view contains the given substring or character
(public member function of std::basic_string_view<CharT,Traits>)
compares two strings
(public member function)
returns a substring
(public member function)