diff options
Diffstat (limited to 'chapter2')
| -rw-r--r-- | chapter2/demo1.cxx | 79 | ||||
| -rw-r--r-- | chapter2/demo2.cxx | 31 | ||||
| -rw-r--r-- | chapter2/newpoint.cxx | 120 | ||||
| -rw-r--r-- | chapter2/newpoint.h | 82 | ||||
| -rw-r--r-- | chapter2/point.cxx | 33 | ||||
| -rw-r--r-- | chapter2/point.h | 49 | ||||
| -rw-r--r-- | chapter2/throttle.cxx | 35 | ||||
| -rw-r--r-- | chapter2/throttle.h | 58 |
8 files changed, 487 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);
+}
diff --git a/chapter2/demo2.cxx b/chapter2/demo2.cxx new file mode 100644 index 0000000..89f4bb6 --- /dev/null +++ b/chapter2/demo2.cxx @@ -0,0 +1,31 @@ +// FILE: demo2.cxx
+// This small demonstration shows how the revised throttle class is used.
+#include <iostream> // Provides cout and cin
+#include <cstdlib> // Provides EXIT_SUCCESS
+#include "throttle.h" // Provides the throttle class
+using namespace std; // Allows all Standard Library items to be used
+using main_savitch_2A::throttle;
+
+const int DEMO_SIZE = 5; // Number of positions in a demonstration throttle
+
+int main( )
+{
+ throttle sample(DEMO_SIZE); // A throttle to use for our demonstration
+ int user_input; // The position that we set the throttle to
+
+ // Set the sample throttle to a position indicated by the user.
+ cout << "I have a throttle with " << DEMO_SIZE << " positions." << endl;
+ cout << "Where would you like to set the throttle?" << endl;
+ cout << "Please type a number from 0 to " << DEMO_SIZE << ": ";
+ cin >> user_input;
+ 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;
+}
diff --git a/chapter2/newpoint.cxx b/chapter2/newpoint.cxx new file mode 100644 index 0000000..f3f40f4 --- /dev/null +++ b/chapter2/newpoint.cxx @@ -0,0 +1,120 @@ +// FILE: newpoint.cxx
+// CLASS IMPLEMENTED: point (See newpoint.h for documentation.)
+
+#include <iostream>
+#include <math.h>
+#include "newpoint.h"
+using namespace std;
+
+namespace main_savitch_2B
+{
+ point::point(double initial_x, double initial_y)
+ {
+ x = initial_x; // Constructor sets point to a given position
+ y = initial_y;
+ }
+
+ void point::shift(double x_amount, double y_amount)
+ {
+ x += x_amount;
+ y += y_amount;
+ }
+
+ void point::rotate90( )
+ {
+ double new_x;
+ double new_y;
+
+ new_x = y; // For a 90 degree clockwise rotation the new y is -1
+ new_y = -x; // times original x, and the new x is the original y
+ x = new_x;
+ y = new_y;
+ }
+
+ bool operator ==(const point& p1, const point& p2)
+ {
+ return
+ (p1.get_x( ) == p2.get_x( ))
+ &&
+ (p1.get_y( ) == p2.get_y( ));
+ }
+
+ bool operator !=(const point& p1, const point& p2)
+ {
+ return !(p1 == p2);
+ }
+
+ point operator +(const point& p1, const point& p2)
+ {
+ double x_sum, y_sum;
+
+ // Compute the x and y of the sum
+ x_sum = (p1.get_x( ) + p2.get_x( ));
+ y_sum = (p1.get_y( ) + p2.get_y( ));
+ point sum(x_sum, y_sum);
+ return sum;
+ }
+
+ ostream& operator <<(ostream& outs, const point& source)
+ // Library facilities used: iostream
+ {
+ outs << source.get_x( ) << " " << source.get_y( );
+ return outs;
+ }
+
+ istream& operator >>(istream& ins, point& target)
+ // Library facilities used: iostream
+ // Friend of: point class
+ {
+ ins >> target.x >> target.y;
+ return ins;
+ }
+
+ int rotations_needed(point p)
+ {
+ int answer;
+
+ answer = 0;
+ while ((p.get_x( ) < 0) || (p.get_y( ) < 0))
+ {
+ p.rotate90( );
+ ++answer;
+ }
+ return answer;
+ }
+
+ void rotate_to_upper_right(point& p)
+ {
+ while ((p.get_x( ) < 0) || (p.get_y( ) < 0))
+ p.rotate90( );
+ }
+
+ double distance(const point& p1, const point& p2)
+ // Library facilities used: cmath
+ {
+ double a, b, c_squared;
+
+ // Calculate differences in x and y coordinates
+ a = p1.get_x( ) - p2.get_x( ); // Difference in x coordinates
+ b = p1.get_y( ) - p2.get_y( ); // Difference in y coordinates
+
+ // Pythagorean Theorem to calculate square of distance between points
+ c_squared = a*a + b*b;
+
+ return sqrt(c_squared); // sqrt calculates square root (from math.h)
+ }
+
+ point middle(const point& p1, const point& p2)
+ {
+ double x_midpoint, y_midpoint;
+
+ // Compute the x and y midpoints
+ x_midpoint = (p1.get_x( ) + p2.get_x( )) / 2;
+ y_midpoint = (p1.get_y( ) + p2.get_y( )) / 2;
+
+ // Construct a new point and return it
+ point midpoint(x_midpoint, y_midpoint);
+ return midpoint;
+ }
+}
+
diff --git a/chapter2/newpoint.h b/chapter2/newpoint.h new file mode 100644 index 0000000..159f1fb --- /dev/null +++ b/chapter2/newpoint.h @@ -0,0 +1,82 @@ +// FILE: newpoint.h (revised from point.h in Figure 2.9 on page 58)
+// CLASS PROVIDED: point (an ADT for a point on a two-dimensional plane)
+//
+// CONSTRUCTOR for the point class:
+// point(double initial_x = 0.0, double initial_y = 0.0)
+// Postcondition: The point has been set to (initial_x, initial_y).
+//
+// MODIFICATION MEMBER FUNCTIONS for the point class:
+// void shift(double x_amount, double y_amount)
+// Postcondition: The point has been moved by x_amount along the x axis
+// and by y_amount along the y axis.
+//
+// void rotate90( )
+// Postcondition: The point has been rotated clockwise 90 degrees.
+//
+// CONSTANT MEMBER FUNCTIONS for the point class:
+// double get_x( ) const
+// Postcondition: The value returned is the x coordinate of the point.
+//
+// double get_y( ) const
+// Postcondition: The value returned is the y coordinate of the point.
+//
+// NONMEMBER FUNCTIONS for the point class:
+// double distance(const point& p1, const point& p2)
+// Postcondition: The value returned is the distance between p1 and p2.
+//
+// point middle(const point& p1, const point& p2)
+// Postcondition: The point returned is halfway between p1 and p2.
+//
+// point operator +(const point& p1, const point& p2)
+// Postcondition: The sum of p1 and p2 is returned.
+//
+// bool operator ==(const point& p1, const point& p2)
+// Postcondition: The return value is true if p1 and p2 are identical.
+//
+// bool operator !=(const point& p1, const point& p2)
+// Postcondition: The return value is true if p1 and p2 are not identical.
+//
+// ostream& operator <<(ostream& outs, const point& source)
+// Postcondition: The x and y coordinates of source have been
+// written to outs. The return value is the ostream outs.
+//
+// istream& operator >>(istream& ins, point& target)
+// Postcondition: The x and y coordinates of target have been
+// read from ins. The return value is the istream ins.
+//
+// VALUE SEMANTICS for the point class:
+// Assignments and the copy constructor may be used with point objects.
+
+#ifndef MAIN_SAVITCH_NEWPOINT_H
+#define MAIN_SAVITCH_NEWPOINT_H
+#include <iostream> // Provides ostream and istream
+
+namespace main_savitch_2B
+{
+ class point
+ {
+ public:
+ // CONSTRUCTOR
+ point(double initial_x = 0.0, double initial_y = 0.0);
+ // MODIFICATION MEMBER FUNCTIONS
+ void shift(double x_amount, double y_amount);
+ void rotate90( );
+ // CONSTANT MEMBER FUNCTIONS
+ double get_x( ) const { return x; }
+ double get_y( ) const { return y; }
+ // FRIEND FUNCTION
+ friend std::istream& operator >>(std::istream& ins, point& target);
+ private:
+ double x, y; // x and y coordinates of this point
+ };
+
+ // NONMEMBER FUNCTIONS for the point class
+ double distance(const point& p1, const point& p2);
+ point middle(const point& p1, const point& p2);
+ point operator +(const point& p1, const point& p2);
+ bool operator ==(const point& p1, const point& p2);
+ bool operator !=(const point& p1, const point& p2);
+ std::ostream& operator <<(std::ostream & outs, const point& source);
+}
+
+#endif
diff --git a/chapter2/point.cxx b/chapter2/point.cxx new file mode 100644 index 0000000..9b56f9e --- /dev/null +++ b/chapter2/point.cxx @@ -0,0 +1,33 @@ +// FILE: point.cxx
+// CLASS IMPLEMENTED: point (See point.h for documentation.)
+
+#include "point.h"
+
+namespace main_savitch_2A
+{
+
+ point::point(double initial_x, double initial_y)
+ {
+ x = initial_x; // Constructor sets the point to a given position.
+ y = initial_y;
+ }
+
+
+ void point::shift(double x_amount, double y_amount)
+ {
+ x += x_amount;
+ y += y_amount;
+ }
+
+
+ void point::rotate90( )
+ {
+ double new_x;
+ double new_y;
+
+ new_x = y; // For a 90 degree clockwise rotation, the new x is the original y,
+ new_y = -x; // and the new y is -1 times the original x.
+ x = new_x;
+ y = new_y;
+ }
+}
diff --git a/chapter2/point.h b/chapter2/point.h new file mode 100644 index 0000000..d1da6a0 --- /dev/null +++ b/chapter2/point.h @@ -0,0 +1,49 @@ +// FILE: point.h
+// CLASS PROVIDED: point (part of the namespace main_savitch_chapter2)
+//
+// CONSTRUCTOR for the point class:
+// point(double initial_x = 0.0, double initial_y = 0.0)
+// Postcondition: The point has been set to (initial_x, initial_y).
+//
+// MODIFICATION MEMBER FUNCTIONS for the point class:
+// void shift(double x_amount, double y_amount)
+// Postcondition: The point has been moved by x_amount along the x axis
+// and by y_amount along the y axis.
+//
+// void rotate90( )
+// Postcondition: The point has been rotated clockwise 90 degrees around
+// the origin.
+//
+// CONSTANT MEMBER FUNCTIONS for the point class:
+// double get_x( ) const
+// Postcondition: The value returned is the x coordinate of the point.
+//
+// double get_y( ) const
+// Postcondition: The value returned is the y coordinate of the point.
+//
+// VALUE SEMANTICS for the point class:
+// Assignments and the copy constructor may be used with point objects.
+
+#ifndef MAIN_SAVITCH_POINT_H
+#define MAIN_SAVITCH_POINT_H
+
+namespace main_savitch_2A
+{
+ class point
+ {
+ public:
+ // CONSTRUCTOR
+ point(double initial_x = 0.0, double initial_y = 0.0);
+ // MODIFICATION MEMBER FUNCTIONS
+ void shift(double x_amount, double y_amount);
+ void rotate90( );
+ // CONSTANT MEMBER FUNCTIONS
+ double get_x( ) const { return x; }
+ double get_y( ) const { return y; }
+ private:
+ double x; // x coordinate of this point
+ double y; // y coordinate of this point
+ };
+}
+
+#endif
diff --git a/chapter2/throttle.cxx b/chapter2/throttle.cxx new file mode 100644 index 0000000..18b0b6a --- /dev/null +++ b/chapter2/throttle.cxx @@ -0,0 +1,35 @@ +// FILE: throttle.cxx
+// CLASS IMPLEMENTED: throttle (See throttle.h for documentation.)
+
+#include <cassert> // Provides assert
+#include "throttle.h" // Provides the throttle class definition
+using namespace std; // Allows all Standard Library items to be used
+
+namespace main_savitch_2A
+{
+
+ throttle::throttle( )
+ { // A simple on-off throttle
+ top_position = 1;
+ position = 0;
+ }
+
+ throttle::throttle(int size)
+ // Library facilities used: cassert
+ {
+ assert(size > 0);
+ top_position = size;
+ position = 0;
+ }
+
+ void throttle::shift(int amount)
+ {
+ position += amount;
+
+ if (position < 0)
+ position = 0;
+ else if (position > top_position)
+ position = top_position;
+ }
+
+}
diff --git a/chapter2/throttle.h b/chapter2/throttle.h new file mode 100644 index 0000000..8707b37 --- /dev/null +++ b/chapter2/throttle.h @@ -0,0 +1,58 @@ +// FILE: throttle.h
+// CLASS PROVIDED: throttle (part of the namespace main_savitch_chapter2)
+//
+// CONSTRUCTORS for the throttle class:
+// throttle( )
+// Postcondition: The throttle has one position above the shut_off position,
+// and it is currently shut off.
+//
+// throttle(int size)
+// Precondition: size > 0.
+// Postcondition: The throttle has size positions above the shut_off
+// position, and it is currently shut off.
+//
+// MODIFICATION MEMBER FUNCTIONS for the throttle class:
+// void shut_off( )
+// Postcondition: The throttle has been turned off.
+//
+// void shift(int amount)
+// Postcondition: The throttle's position has been moved by
+// amount (but not below 0 or above the top position).
+//
+// CONSTANT MEMBER FUNCTIONS for the throttle class:
+// double flow( ) const
+// Postcondition: The value returned is the current flow as a
+// proportion of the maximum flow.
+//
+// bool is_on( ) const
+// Postcondition: If the throttle's flow is above 0 then
+// the function returns true; otherwise it returns false.
+//
+// VALUE SEMANTICS for the throttle class: (See discussion on page 51.)
+// Assignments and the copy constructor may be used with throttle objects.
+
+#ifndef MAIN_SAVITCH_THROTTLE
+#define MAIN_SAVITCH_THROTTLE
+
+namespace main_savitch_2A
+{
+ class throttle
+ {
+ public:
+ // CONSTRUCTORS
+ throttle( );
+ throttle(int size);
+ // MODIFICATION MEMBER FUNCTIONS
+ void shut_off( ) { position = 0; }
+ void shift(int amount);
+ // CONSTANT MEMBER FUNCTIONS
+ double flow( ) const { return position / double(top_position); }
+ bool is_on( ) const { return (position > 0); }
+ private:
+ int top_position;
+ int position;
+ };
+
+}
+
+#endif
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