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ChrisMayfieldChrisMayfield
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ch04 revisions
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‎ch04/Circle.java‎

Lines changed: 3 additions & 66 deletions
Original file line numberDiff line numberDiff line change
@@ -1,76 +1,13 @@
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public class Circle {
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public static double calculateArea(double radius) {
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double result = Math.PI * radius * radius;
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return result;
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}
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public static double calculateArea2(double radius) {
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return Math.PI * radius * radius;
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}
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public static double distance
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(double x1, double y1, double x2, double y2) {
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double dx = x2 - x1;
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double dy = y2 - y1;
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System.out.println("dx is " + dx);
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System.out.println("dy is " + dy);
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return 0.0;
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}
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public static double distance2
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(double x1, double y1, double x2, double y2) {
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double dx = x2 - x1;
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double dy = y2 - y1;
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double dsquared = dx * dx + dy * dy;
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System.out.println("dsquared is " + dsquared);
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return 0.0;
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}
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public static double distance3
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(double x1, double y1, double x2, double y2) {
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double dx = x2 - x1;
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double dy = y2 - y1;
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double dsquared = dx * dx + dy * dy;
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double result = Math.sqrt(dsquared);
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return result;
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}
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public static double circleArea
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(double xc, double yc, double xp, double yp) {
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double radius = distance(xc, yc, xp, yp);
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double area = calculateArea(radius);
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return area;
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}
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public static double calculateArea
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(double xc, double yc, double xp, double yp) {
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return calculateArea(distance(xc, yc, xp, yp));
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}
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public static void main(String[] args) {
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System.out.println("calculateArea");
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System.out.println(calculateArea(3.0));
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System.out.println("calculateArea2");
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System.out.println(calculateArea2(3.0));
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System.out.println("distance");
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System.out.println(distance(1.0, 2.0, 4.0, 6.0));
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System.out.println("distance2");
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System.out.println(distance2(1.0, 2.0, 4.0, 6.0));
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System.out.println("distance3");
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System.out.println(distance3(1.0, 2.0, 4.0, 6.0));
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System.out.println("circleArea");
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System.out.println(circleArea(1.0, 2.0, 4.0, 6.0));
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System.out.println("calculateArea with 4 doubles");
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System.out.println(calculateArea(1.0, 2.0, 4.0, 6.0));
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8+
double diameter = 10.0;
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double area = calculateArea(diameter / 2);
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System.out.println(area);
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}
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}

‎ch04/Distance.java‎

Lines changed: 45 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,45 @@
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public class Distance {
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public static double distance1(double x1, double y1, double x2, double y2) {
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return 0.0; // stub
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}
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public static double distance2(double x1, double y1, double x2, double y2) {
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double dx = x2 - x1;
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double dy = y2 - y1;
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System.out.println("dx is " + dx);
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System.out.println("dy is " + dy);
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return 0.0; // stub
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}
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public static double distance3(double x1, double y1, double x2, double y2) {
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double dx = x2 - x1;
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double dy = y2 - y1;
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double dsquared = dx * dx + dy * dy;
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System.out.println("dsquared is " + dsquared);
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return 0.0; // stub
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}
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public static double distance4(double x1, double y1, double x2, double y2) {
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double dx = x2 - x1;
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double dy = y2 - y1;
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double dsquared = dx * dx + dy * dy;
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double result = Math.sqrt(dsquared);
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return result;
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}
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public static void main(String[] args) {
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System.out.println("\ndistance version 1");
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System.out.println(distance1(1.0, 2.0, 4.0, 6.0));
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System.out.println("\ndistance version 2");
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System.out.println(distance2(1.0, 2.0, 4.0, 6.0));
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System.out.println("\ndistance version 3");
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System.out.println(distance3(1.0, 2.0, 4.0, 6.0));
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System.out.println("\ndistance version 4");
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System.out.println(distance4(1.0, 2.0, 4.0, 6.0));
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}
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}

ch04/Methods.java renamed to ch04/MathMethods.java

Lines changed: 5 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,4 @@
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/**
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* Examples from Chapter 4.
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*/
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public class Methods {
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public class MathMethods {
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public static void main(String[] args) {
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double root = Math.sqrt(17.0);
@@ -10,10 +7,14 @@ public static void main(String[] args) {
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118
double degrees = 90;
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double angle2 = degrees / 180.0 * Math.PI;
10+
1311
double radians = Math.toRadians(180.0);
1412
double degrees2 = Math.toDegrees(Math.PI);
13+
1514
long x = Math.round(Math.PI * 20.0);
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16+
// examples of composition
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double x2 = Math.cos(angle + Math.PI / 2.0);
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double x3 = Math.exp(Math.log(10.0));
1920
double x4 = Math.pow(2.0, 10.0);

‎ch04/PrintTime.java‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -10,6 +10,9 @@ public static void main(String[] args) {
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int hour = 11;
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int minute = 59;
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printTime(hour, minute);
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// additional example for stack diagram
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printTime(hour + 1, 0);
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}
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}

‎ch04/PrintTwice.java‎

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Original file line numberDiff line numberDiff line change
@@ -7,6 +7,9 @@ public static void printTwice(String s) {
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public static void main(String[] args) {
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printTwice("Don't make me say this twice!");
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String message = "Never say never.";
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printTwice(message);
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}
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}

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