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| author | Fuwn <[email protected]> | 2024-04-07 23:18:32 -0700 |
|---|---|---|
| committer | Fuwn <[email protected]> | 2024-04-07 23:18:32 -0700 |
| commit | c1b6ffe70bd281c6c230fd63fabcaac2aff47514 (patch) | |
| tree | e8af3b1782a7cd0754590ed618fddc1bdb9b7385 /chapter2/demo1.cxx | |
| download | dscode-main.tar.xz dscode-main.zip | |
Diffstat (limited to 'chapter2/demo1.cxx')
| -rw-r--r-- | chapter2/demo1.cxx | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/chapter2/demo1.cxx b/chapter2/demo1.cxx new file mode 100644 index 0000000..4c8bcca --- /dev/null +++ b/chapter2/demo1.cxx @@ -0,0 +1,79 @@ +// FILE: demo1.cxx
+// This small demonstration shows how the throttle class is used.
+
+#include <iostream> // Provides cout and cin
+#include <cstdlib> // Provides EXIT_SUCCESS
+using namespace std; // Allows all Standard Library items to be used
+class throttle
+{
+public:
+ // MODIFICATION MEMBER FUNCTIONS
+ void shut_off( );
+ void shift(int amount);
+ // CONSTANT MEMBER FUNCTIONS
+ double flow( ) const;
+ bool is_on( ) const;
+private:
+ int position;
+};
+
+int main( )
+{
+ throttle sample;
+ int user_input;
+ // Set the sample throttle to a position indicated by the user.
+ cout << "I have a throttle with 6 positions." << endl;
+ cout << "Where would you like to set the throttle? " << endl;
+ cout << "Please type a number from 0 to 6: ";
+ cin >> user_input;
+ sample.shut_off( );
+ sample.shift(user_input);
+ // Shift the throttle down to zero, printing the flow along the way.
+ while (sample.is_on( ))
+ {
+ cout << "The flow is now " << sample.flow( ) << endl;
+ sample.shift(-1);
+ }
+ cout << "The flow is now off" << endl;
+ return EXIT_SUCCESS;
+}
+
+void throttle::shut_off( )
+// Precondition: None.
+// Postcondition: The throttle has been turned off.
+{
+ position = 0;
+}
+
+double throttle::flow( ) const
+// Precondition: shut_off has been called at least once to initialize the
+// throttle.
+// Postcondition: The value returned is the current flow as a proportion of
+// the maximum flow.
+{
+ return position / 6.0;
+}
+
+void throttle::shift(int amount)
+// Precondition: shut_off has been called at least once to initialize the
+// throttle.
+// Postcondition: The throttle's position has been moved by amount (but not
+// below 0 or above 6).
+{
+ position += amount;
+
+ // Adjust the throttle if it went too high or too low
+ if (position < 0)
+ position = 0;
+ else if (position > 6)
+ position = 6;
+}
+
+bool throttle::is_on( ) const
+// Precondition: shut_off has been called at least once to initialize the
+// throttle.
+// Postcondition: If the throttle's flow is above 0 then the function
+// returns true; otherwise it returns false.
+{
+ return (flow( ) > 0);
+}
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