68 lines
2.6 KiB
C++
68 lines
2.6 KiB
C++
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// fig20_03.cpp
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// Demonstrating namespaces.
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#include <fmt/format.h>
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#include <iostream>
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int integer1{98}; // global variable
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// create namespace Example
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namespace Example {
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// declare two constants and one variable
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const double pi{3.14159};
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const double e{2.71828};
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int integer1{8};
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void printValues(); // prototype
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// nested namespace
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namespace Inner {
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// define enumeration
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enum Years { fiscal1 = 2020, fiscal2, fiscal3 };
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}
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}
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// create unnamed namespace
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namespace {
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double doubleInUnnamed{88.22}; // declare variable
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}
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int main() {
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// output value doubleInUnnamed of unnamed namespace
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std::cout << fmt::format("doubleInUnnamed = {}\n", doubleInUnnamed);
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// output global variable
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std::cout << fmt::format("(global) integer1 = {}\n", integer1);
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// output values of Example namespace
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std::cout << fmt::format(
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"pi = {}\ne = {}\ninteger1 = {}\nfiscal3 = {}\n", Example::pi,
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Example::e, Example::integer1, Example::Inner::fiscal3);
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Example::printValues(); // invoke printValues function
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}
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// display variable and constant values
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void Example::printValues() {
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std::cout << "\nIn printValues:\n";
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std::cout << fmt::format(
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"integer1 = {}\npi = {}\ne = {}\n", integer1, pi, e);
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std::cout << fmt::format(
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"doubleInUnnamed = {}\n(global) integer1 = {}\nfiscal3 = {}\n",
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doubleInUnnamed, ::integer1, Inner::fiscal3);
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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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