public class SimpleMath
1: import java.util.Scanner;
3: /**
4: * An application to demonstrate variables and simple math
5: *
6: * @author Mark Young (A00000000)
7: * @version 1.1 2011-05-13
8: */
9: public class SimpleMath {
10: // this variable is called a CONSTANT:
11: public static final double MIDTERM_WEIGHT = 0.20;
12: // it is declared outside the main method (any method, actually)
13: // its declaration starts with "public static final"
14: // its name is in ALL_CAPITALS (with _ between the words)
15: // its value cannot be changed
17: public static void main(String[] args) {
18: // declare some variables
19: int midtermScore = 78;
20: double midtermWeighted = midtermScore * MIDTERM_WEIGHT;
21: char letterGrade = 'C';
22: boolean failedMidterm = false;
23: Scanner kbd = new Scanner(System.in);
25: // describe self
26: System.out.println();
27: System.out.println("Using Variables");
28: System.out.println("---------------");
29: System.out.println();
31: // print variables & values
32: System.out.println("midtermScore is " + midtermScore);
33: System.out.println("midtermWeighted is " + midtermWeighted);
34: System.out.println("letterGrade is " + letterGrade);
35: System.out.println("failedMidterm is " + failedMidterm);
36: System.out.println();
37: System.out.print("Please press Enter key...");
38: kbd.nextLine();
39: System.out.println();
41: // Some simple math
42: System.out.println("7 + 3 is " + (7 + 3));
43: System.out.println("7.0 + 3.0 is " + (7.0 + 3.0));
44: System.out.println("7 - 3 is " + (7 - 3));
45: System.out.println("7.0 - 3.0 is " + (7.0 - 3.0));
46: System.out.println("7 * 3 is " + (7 * 3));
47: System.out.println("7.0 * 3.0 is " + (7.0 * 3.0));
48: System.out.println("7 / 3 is " + (7 / 3));
49: System.out.println("7.0 / 3.0 is " + (7.0 / 3.0));
50: System.out.println("7 % 3 is " + (7 % 3));
51: System.out.println("7.0 % 3.0 is " + (7.0 % 3.0));
52: System.out.println();
53: System.out.print("Please press Enter key...");
54: kbd.nextLine();
55: System.out.println();
57: // math using variables
58: int m, n;
59: System.out.println(" m n");
60: m = 3 + 5;
61: System.out.println("m = 3 + 5; " + m + " ?");
62: n = 4 * m;
63: System.out.println("n = 4 * m; " + m + " " + n);
64: m = n % 5;
65: System.out.println("m = n % 5; " + m + " " + n);
66: n = n / 5;
67: System.out.println("n = n / 5; " + m + " " + n);
68: System.out.print("Please press Enter key...");
69: kbd.nextLine();
70: System.out.println();
71:
72: // be careful of order-of-operations!
73: n = m + 8 / m + 3;
74: System.out.println("n = m + 8 / m + 3; " + m + " " + n);
75: n = (m + 8) / (m + 3);
76: System.out.println("n = (m + 8) / (m + 3); " + m + " " + n);
77: System.out.println();
78: System.out.print("Please press Enter key...");
79: kbd.nextLine();
80: System.out.println();
82: // with parentheses
83: System.out.println("3*6+4/2 = " + (3*6+4/2));
84: System.out.println("3*(6+4)/2 = " + (3*(6+4)/2));
85: System.out.println("3*(6+4/2) = " + (3*(6+4/2)));
86: System.out.println("2+2+2*3 = " + (2+2+2*3));
87: System.out.println();
88: System.out.print("Please press Enter key...");
89: kbd.nextLine();
90: System.out.println();
92: // mixed mode expressions
93: System.out.println("3.6 + 4 / 2 = " + (3.6 + 4 / 2));
94: System.out.println("3.6 + 5 / 2 = " + (3.6 + 5 / 2));
95: System.out.println("(3.6 + 5) / 2 = " + ((3.6 + 5) / 2));
96: System.out.println();
97: System.out.print("Please press Enter key...");
98: kbd.nextLine();
99: System.out.println();
101: // type casting
102: System.out.println("45 / 4 = " + (45 / 4));
103: System.out.println("(double)45 / (double)4 = "
104: + ((double)45 / (double)4));
105: System.out.println("(int)19.95 = " + ((int)19.95));
106: System.out.println();
107: System.out.print("Please press Enter key...");
108: kbd.nextLine();
109: System.out.println();
110: }
112: }