80 lines
2.9 KiB
C++
80 lines
2.9 KiB
C++
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// fig05_06.cpp
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// Scoping example.
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#include <iostream>
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using namespace std;
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void useLocal(); // function prototype
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void useStaticLocal(); // function prototype
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void useGlobal(); // function prototype
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int x{1}; // global variable
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int main() {
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cout << "global x in main is " << x << '\n';
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const int x{5}; // local variable to main
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cout << "local x in main's outer scope is " << x << '\n';
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{ // block starts a new scope
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const int x{7}; // hides both x in outer scope and global x
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cout << "local x in main's inner scope is " << x << '\n';
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}
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cout << "local x in main's outer scope is " << x << '\n';
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useLocal(); // useLocal has local x
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useStaticLocal(); // useStaticLocal has static local x
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useGlobal(); // useGlobal uses global x
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useLocal(); // useLocal reinitializes its local x
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useStaticLocal(); // static local x retains its prior value
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useGlobal(); // global x also retains its prior value
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cout << "\nlocal x in main is " << x << '\n';
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}
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// useLocal reinitializes local variable x during each call
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void useLocal() {
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int x{25}; // initialized each time useLocal is called
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cout << "\nlocal x is " << x << " on entering useLocal\n";
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++x;
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cout << "local x is " << x << " on exiting useLocal\n";
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}
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// useStaticLocal initializes static local variable x only the
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// first time the function is called; value of x is saved
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// between calls to this function
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void useStaticLocal() {
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static int x{50}; // initialized first time useStaticLocal is called
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cout << "\nlocal static x is " << x
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<< " on entering useStaticLocal\n";
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++x;
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cout << "local static x is " << x <<
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" on exiting useStaticLocal\n";
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}
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// useGlobal modifies global variable x during each call
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void useGlobal() {
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cout << "\nglobal x is " << x << " on entering useGlobal\n";
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x *= 10;
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cout << "global x is " << x << " on exiting useGlobal\n";
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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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