-
Notifications
You must be signed in to change notification settings - Fork 0
/
Parser.cs
84 lines (67 loc) · 1.99 KB
/
Parser.cs
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
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Translator
{
class Parser
{
}
class ExprNode
{
char c;
ExprNode operand1;
ExprNode operand2;
ExprNode(char num)
{
c = num;
operand1 = operand2 = null;
}
ExprNode(char op, ExprNode e1, ExprNode e2)
{
c = op;
operand1 = e1;
operand2 = e2;
}
ExprNode parse(string input)
{
string[] operatorStack = new string[50];
string[] exprStack = new string[50];
char c;
while (c = input.getNextChar())
{
if (c == '(')
operatorStack.push(c);
else if (c.isDigit())
exprStack.push(ExprNode(c));
else if (c.isOperator())
{
while (operatorStack.top().precedence >= c.precedence)
{
operator = operatorStack.pop();
e2 = exprStack.pop();
e1 = exprStack.pop();
exprStack.push(ExprNode(operator, e1, e2));
}
operatorStack.push(c);
}
else if (c == ')')
{
while (operatorStack.top() != '(')
{
op = operatorStack.pop();
e2 = exprStack.pop();
e1 = exprStack.pop();
}
exprStack.push(ExprNode(operator, e1, e2));
}
operatorStack.pop()
else
{
error();
return null;
}
return exprStack.pop();
}
}