56 lines
2.3 KiB
C++
56 lines
2.3 KiB
C++
// fig08_09.cpp
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// C++17 string_view.
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#include <fmt/format.h>
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#include <iostream>
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#include <string>
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#include <string_view>
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int main() {
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std::string s1{"red"};
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std::string s2{s1};
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std::string_view v1{s1}; // v1 "sees" the contents of s1
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std::cout << fmt::format("s1: {}\ns2: {}\nv1: {}\n\n", s1, s2, v1);
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// string_views see changes to the characters they view
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s1.at(0) = 'R'; // capitalize s1
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std::cout << fmt::format("s1: {}\ns2: {}\nv1: {}\n\n", s1, s2, v1);
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// string_views are comparable with strings or string_views
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std::cout << fmt::format("s1 == v1: {}\ns2 == v1: {}\n\n",
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s1 == v1, s2 == v1);
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// string_view can remove a prefix or suffix
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v1.remove_prefix(1); // remove one character from the front
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v1.remove_suffix(1); // remove one character from the back
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std::cout << fmt::format("s1: {}\nv1: {}\n\n", s1, v1);
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// string_views are iterable
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std::string_view v2{"C-string"};
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std::cout << "The characters in v2 are: ";
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for (char c : v2) {
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std::cout << c << " ";
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}
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// string_views enable various string operations on C-Strings
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std::cout << fmt::format("\n\nv2.size(): {}\n", v2.size());
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std::cout << fmt::format("v2.find('-'): {}\n", v2.find('-'));
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std::cout << fmt::format("v2.starts_with('C'): {}\n",
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v2.starts_with('C'));
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}
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/**************************************************************************
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* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
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* Pearson Education, Inc. All Rights Reserved. *
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* *
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* DISCLAIMER: The authors and publisher of this book have used their *
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* best efforts in preparing the book. These efforts include the *
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* development, research, and testing of the theories and programs *
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* to determine their effectiveness. The authors and publisher make *
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* no warranty of any kind, expressed or implied, with regard to these *
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* programs or to the documentation contained in these books. The authors *
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* and publisher shall not be liable in any event for incidental or *
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* consequential damages in connection with, or arising out of, the *
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* furnishing, performance, or use of these programs. *
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**************************************************************************/
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