Defina uma nova classe que represente uma porta lógica AND com três entradas. Esta classe deve chamar-se AndGate3 e apresenta a mesma funcionalidade que a de duas entradas. A apresentação (toString) é A: valor B: valor C: valor.
A classe AndGate3 deve ser definida reutilizando o conceito AndGate2 (definido no Exercício 1).
Adapte a função main definida anteriormente, por forma a integrar alguns testes com a nova porta lógica.
In this solution we observe that the operation is a specialization of the previous one. This allows us to reuse the previous functionality.
| Ficheiro AndGate3i.java |
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1 /** Logical AND gate (inheritance). */
2 public class AndGate3i extends AndGate2 {
3 /** A new input is needed (the other two are inherited). */
4 private boolean _c = false;
5
6 /**
7 * Default constructor: false for all inputs.
8 */
9 public AndGate3i() {
10 //super(); //default: explicit call not needed
11 }
12
13 /**
14 * Inputs receive same value.
15 *
16 * @param v
17 * the input value.
18 */
19 public AndGate3i(boolean v) {
20 super(v);
21 _c = v;
22 }
23
24 /**
25 * Arbitrary input value combinations.
26 *
27 * @param a
28 * input value
29 * @param b
30 * input value
31 * @param c
32 * input value
33 */
34 public AndGate3i(boolean a, boolean b, boolean c) {
35 super(a, b);
36 _c = c;
37 }
38
39 /**
40 * @return third input value.
41 */
42 public boolean getC() {
43 return _c;
44 }
45
46 /**
47 * Set input value.
48 *
49 * @param c
50 * input value.
51 */
52 public void setC(boolean c) {
53 _c = c;
54 }
55
56 /**
57 * @return value of logical AND operation.
58 */
59 @Override
60 public boolean getOutput() {
61 return super.getOutput() && _c;
62 }
63
64 /**
65 * @see java.lang.Object#equals(java.lang.Object)
66 */
67 @Override
68 public boolean equals(Object other) {
69 if (other instanceof AndGate3i) {
70 AndGate3i andGate = (AndGate3i) other;
71 return super.equals(other) && _c == andGate.getC();
72 }
73 return false;
74 }
75
76 /**
77 * @see java.lang.Object#toString()
78 */
79 @Override
80 @SuppressWarnings("nls")
81 public String toString() {
82 return super.toString() + " C:" + _c;
83 }
84 }
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In this solution, the 3-input gate is defined as a composition of 2-input gates. Note that the A-input of the second gate is updated whenever the inputs of the first gate are changed.
| Ficheiro AndGate3c.java |
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| {{{2}}} |