Calculator/Calculator.java at main · xararas/Calculator · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
import java.util.Scanner;

public class Calculator
{
	public static float result;
	public boolean isNotValid = false;
	public static float memoryVal;

	public static void main(String[] args)
	{
		String exp;
		String exp2;
		Scanner in = new Scanner(System.in);
		Calculator calc = new Calculator();
		System.out.println("Enter the expression");
		exp = in.nextLine();
		result = calc.evaluate(exp);
		System.out.println(result);

		while (exp != "")
		{
			System.out.println("Enter the expression");
			exp = in.nextLine();
			if (exp.equals("m"))
			{
				calc.setMemoryValue(result);
			}

			else
			{
				result = calc.evaluate(exp);
				System.out.println(result);
			}

			System.out.println("Enter the expression");
			exp = in.nextLine();
			float memVal;
			if (exp.equals("mr"))
			{
				memVal = calc.getMemoryValue();
				System.out.println(memVal);
			}

			else
			{
				result = calc.evaluate(exp);
				System.out.println(result);
			}

			System.out.println("Enter the expression");
			exp = in.nextLine();
			if (exp.equals("c"))
			{	calc.clearMemory();
			System.out.println(calc.getMemoryValue());
			}

			else
			{
				result = calc.evaluate(exp);
				System.out.println(result);
			}
		}
	}

	public Calculator()
	{

	}

	public float evaluate(String expression)
	{

		String[] tokens = expression.split(" ");

		if(tokens.length != 3)
		{
			System.out.println("Invalid input");
			return Float.MIN_VALUE;
		}

		if(tokens[0].equals("") && tokens[1] != "" && tokens[2] != "")
		{
			System.out.println("Invalid input");
			return Float.MIN_VALUE;
		}

		if(tokens[0] != "" && tokens[1] != "" && tokens[2].equals(""))
		{
			System.out.println("Invalid input");
			return Float.MIN_VALUE;
		}

		float operand1 = Float.parseFloat(tokens[0]);
		float operand2 = Float.parseFloat(tokens[2]);


		String op = tokens[1];

		float i = 0;

		switch (op)
		{
		case "+":
			i = operand1 + operand2;
			break;

		case "-":
			i = operand1 - operand2;
			break;

		case "*":
			i = operand1 * operand2;
			break;

		case "/":

			if(operand2 != 0)
				i = operand1 / operand2;
			else
			{
				System.out.println("Invalid input");
				return Float.MIN_VALUE;
			}
			break;

		default:
			System.out.println("Invalid input");
		}

		return result = i;
	}

	public float getCurrentValue()
	{
		return result;
	}

	public void setMemoryValue(float memval)
	{
		memoryVal = memval;
	}

	public float getMemoryValue()
	{
		return memoryVal;
	}


	public void clearMemory()
	{
		setMemoryValue(0);
	}

	public float getHistoryValue(int index)
	{
		return index;
	}
}