29 lines
837 B
C++
29 lines
837 B
C++
// support.cpp -- use external variable
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// compile with external.cpp
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#include <iostream>
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extern double warming; // use warming from another file
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// function prototypes
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void update(double dt);
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void local();
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using std::cout;
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void update(double dt) // modifies global variable
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{
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extern double warming; // optional redeclaration
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warming += dt; // uses global warming
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cout << "Updating global warming to " << warming;
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cout << " degrees.\n";
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}
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void local() // uses local variable
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{
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double warming = 0.8; // new variable hides external one
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cout << "Local warming = " << warming << " degrees.\n";
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// Access global variable with the
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// scope resolution operator
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cout << "But global warming = " << ::warming;
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cout << " degrees.\n";
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}
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