37 lines
1.5 KiB
C++
37 lines
1.5 KiB
C++
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// fig15_09.cpp
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// Testing custom concepts with static_assert.
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#include <iostream>
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#include <string>
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template<typename T>
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concept Numeric = std::integral<T> || std::floating_point<T>;
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template<typename T>
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auto multiply(T a, T b) {
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static_assert(Numeric<T>);
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return a * b;
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}
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int main() {
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using namespace std::string_literals;
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multiply(2, 5); // OK: int is Numeric
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multiply(2.5, 5.5); // OK: double is Numeric
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multiply("2"s, "5"s); // error: string is not Numeric
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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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