1    package bookExamples.ch03Ops; 
2     
3     
4    public class Operations { 
5        public static void main(String args[]) { 
6            parenthesesDemo(); 
7            memberSelectionDemo(); 
8            separationDemo(); 
9            postIncrementDemo(); 
10           postDecrementDemo(); 
11           preIncrementDemo(); 
12           preDecrementDemo(); 
13           plusDemo(); 
14           minusDemo(); 
15           multiplicationDemo(); 
16           divisionDemo(); 
17           modulusDemo(); 
18           additionDemo(); 
19           subtractionDemo(); 
20           equalsDemo(); 
21           plusEqualsDemo(); 
22           minusEqualsDemo(); 
23           multiplyEqualsDemo(); 
24           divideEqualsDemo(); 
25           modulusEqualsDemo(); 
26       } 
27    
28       public static void parenthesesDemo() { 
29           int x = 4, y = 2, z = 1; 
30           hr(); 
31           print("x = 4, y = 2, and z = 1" 
32                   + "\nso when you calculate " 
33                   + "x * (y + z)" 
34                   + "the result is " 
35                   + (x * (y + z))); 
36           print("x = 4, y = 2, and z = 1" 
37                   + "\nso when you calculate" 
38                   + " (x * y) + z the result is " 
39                   + ((x * y) + z)); 
40       } 
41    
42       public static void memberSelectionDemo() { 
43    
44           int x = 0; 
45           hr(); 
46           print("if we call Math.cos(x) when x = 0 " 
47                   + "using the member" 
48                   + "selection\nwe can " 
49                   + "invoke method " 
50                   + "cos of the Math class, " 
51                   + "the result is " 
52                   + Math.cos(x)); 
53       } 
54    
55       public static void separationDemo() { 
56           int x = 4, y = 2; 
57           hr(); 
58           print("if we call Math.pow(x,y) " 
59                   + "when x = 4 " 
60                   + "and y = 2 using the " 
61                   + "separation" 
62                   + "\nwe can invoke method " 
63                   + "pow of the Math class," 
64                   + "the result is " + Math.pow(x, y)); 
65       } 
66    
67       public static void plusDemo() { 
68           int x = 4; 
69           hr(); 
70           print("x = 4 but +x = " 
71                   + (+x)); 
72       } 
73    
74       public static void minusDemo() { 
75           int x = 4; 
76           hr(); 
77           print("x = 4 but -x = " 
78                   + (-x)); 
79       } 
80    
81       public static void postIncrementDemo() { 
82           int x = 0; 
83           hr(); 
84           print("x = 0 but x++ = " 
85                   + x++); 
86           print("after x++, x = " 
87                   + x); 
88       } 
89    
90       public static void postDecrementDemo() { 
91           int x = 0; 
92           hr(); 
93           print("x = 0 but x-- = " 
94                   + x--); 
95           print("after x--, x = " 
96                   + x); 
97       } 
98    
99       public static void preIncrementDemo() { 
100          int x = 0; 
101          hr(); 
102          print("x = 0 but ++x = " 
103                  + ++x); 
104          print("after ++x, x = " 
105                  + x); 
106      } 
107   
108      public static void preDecrementDemo() { 
109          int x = 0; 
110          hr(); 
111          print("x = 0 but --x = " 
112                  + --x); 
113          print("after --x, x = " 
114                  + x); 
115      } 
116   
117      public static void additionDemo() { 
118          int x = 4, y = 2; 
119          hr(); 
120          print("x = 4 and y = 2" 
121                  + "\nso x + y = " 
122                  + (x + y)); 
123      } 
124   
125      public static void subtractionDemo() { 
126          int x = 4, y = 2; 
127          hr(); 
128          print("x = 4 and y = 2" 
129                  + "\nso x - y = " 
130                  + (x - y)); 
131      } 
132   
133      public static void multiplicationDemo() { 
134          int x = 4, y = 2; 
135          hr(); 
136          print("x = 4 and y = 2\nso x * y = " 
137                  + (x * y)); 
138      } 
139   
140      public static void divisionDemo() { 
141          int x = 4, y = 2; 
142          hr(); 
143          print("x = 4 and y = 2\nso x / y = " 
144                  + (x / y)); 
145      } 
146   
147      public static void modulusDemo() { 
148          int x = 4, y = 2; 
149          hr(); 
150          print("x = 4 and y = 2" 
151                  + "\nso x % y = " + (x % y)); 
152      } 
153   
154      public static void equalsDemo() { 
155          int x = 4, y = 2; 
156          hr(); 
157          print("x = 4, y = 2\nso x = y " 
158                  + "makes x equal to " 
159                  + (x = y)); 
160      } 
161   
162      public static void plusEqualsDemo() { 
163          int x = 4, y = 2; 
164          hr(); 
165          print("x = 4 and y = 2\nso x += y makes" 
166                  + "x equal to " + (x += y)); 
167      } 
168   
169      public static void minusEqualsDemo() { 
170          int x = 4, y = 2; 
171          hr(); 
172          print("x = 4 and y = 2" 
173                  + "\nso x -= y " 
174                  + "makes x equal to " 
175                  + (x -= y)); 
176      } 
177   
178      public static void multiplyEqualsDemo() { 
179          int x = 4, y = 2; 
180          hr(); 
181          print("x = 4 and y = 2" 
182                  + "\nso x *= y makes " 
183                  + "x equal to " 
184                  + (x *= y)); 
185      } 
186   
187      public static void divideEqualsDemo() { 
188          int x = 4, y = 2; 
189          hr(); 
190          print("x = 4 and y = 2" 
191                  + "\nso x /= y makes x equal to " 
192                  + (x /= y)); 
193      } 
194   
195      public static void modulusEqualsDemo() { 
196          int x = 4, y = 2; 
197          hr(); 
198          print("x = 4 and y = 2\n" 
199                  + "so x %= y makes x equal to " 
200                  + (x %= y)); 
201      } 
202   
203      public static void hr() { 
204          print("____________________________"); 
205      } 
206   
207      public static void print(Object o) { 
208          System.out.println(o); 
209      } 
210  } 
211