Resume/FunctionProject at main · Defiantearth/Resume · 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
import javax.swing.JOptionPane;
public class FunctionProject
{

  public static int parseInt(String s)
  { if(s.equals("0"))
    { return 0;}

    if(s.charAt(0)=='0')
    { System.out.println("Invalid expression, try again.");
      System.exit(0);}

    int sum=0;
    int p=1;
    for (int i = s.length()-1; i >= 0; i--)
    { if(Character.isDigit(s.charAt(i)))
      { int num = s.charAt(i) - '0';
        sum=sum+num*p;
        p = p*10; }
      else
      { System.out.println("Invalid expression, try again.");
        System.exit(0);}
    }
    return sum;
  }

  //evals expression
  public static int eval(String ex)
  { int add=0, sub=0, mul=0, div=0, par=0;

    for(int i=0;ex.length()>i;i++)
    { if(ex.charAt(i)=='(')
      { par++;}
        { if(ex.charAt(i)==')')
        { par--;}
           { if(par==0)
               { if(ex.charAt(i)=='+')
                    { add=i;}
                   { if(ex.charAt(i)=='-')
                        { sub=i;}
                        { if(ex.charAt(i)=='*')
                             { mul=i;}
                             { if(ex.charAt(i)=='/')
                                  { div=i;}
    }}}}}}}
    if(add>0)
    { return eval(ex.substring(0,add)) + eval(ex.substring(add+1));}
    else
    { if(sub>0)
      { return eval(ex.substring(0,sub)) - eval(ex.substring(sub+1));}
      else
      { if(mul>0)
        { return eval(ex.substring(0,mul)) * eval(ex.substring(mul+1));}
        else
        { if(div>0)
          { return eval(ex.substring(0,div)) / eval(ex.substring(div+1));}
          else
          { if(ex.charAt(0)=='(')
            { return eval(ex.substring(1, ex.length()-1));}
            else
            { return parseInt(ex);}
  }}}}}
  public static void main(String[] args)
  { String ex =  JOptionPane.showInputDialog("Enter Expression");
   System.out.println(eval(ex));
  }
}