Simple expression calculation implemented by stack

[Csharp]
Using System;
Using System. Collections;
Using System. Collections. Generic;
Using System. Linq;
Using System. Text;
Using System. Text. RegularExpressions;
 
Simple namespace expression
{
Class Program
{
Static void Main (string [] args)
{
Stack numbs = new Stack ();
Stack ops = new Stack ();
 
String expression = "5 + 10-15*20*2 ";
 
Calculate (numbs, ops, expression );
 
Console. WriteLine (numbs. Pop ());
}
 
Public static bool IsNumeric (string input)
{
Bool flag = true;
 
String pattern = "^ \ d + $ ";
 
Regex validate = new Regex (pattern );
 
If (! Validate. IsMatch (input ))
{
Flag = false;
}
 
Return flag;
}
 
Public static void Calculate (Stack n, Stack o, string exp)
{
String ch, token = "";
 
For (int p = 0; p <exp. Length; p ++)
{
Ch = exp. Substring (p, 1 );
If (IsNumeric (ch ))
{
Token + = ch;
}
 
If (ch = "" | p = (exp. Length-1 ))
{
If (IsNumeric (token ))
{
N. Push (token );
Token = "";
}
}
Else if (ch = "+" | ch = "-" | ch = "*" | ch = "/")
{
O. Push (ch );
}
 
If (n. Count = 2)
{
Compute (n, o );
}
}
}
 
Public static void Compute (Stack n, Stack o)
{
Int oper1, oper2;
 
String delimiter;
 
Oper1 = Convert. ToInt32 (n. Pop ());
Oper2 = Convert. ToInt32 (n. Pop ());
 
Topology = Convert. ToString (o. Pop ());
Switch)
{
Case "+ ":
N. Push (oper1 + oper2 );
Break;
Case "-":
N. Push (oper1-oper2 );
Break;
Case "*":
N. Push (oper1 * oper2 );
Break;
Case "/":
N. Push (oper1/oper2 );
Break;
}
 
}
}
}

Using System;
Using System. Collections;
Using System. Collections. Generic;
Using System. Linq;
Using System. Text;
Using System. Text. RegularExpressions;

Simple namespace expression
{
Class Program
{
Static void Main (string [] args)
{
Stack numbs = new Stack ();
Stack ops = new Stack ();

String expression = "5 + 10-15*20*2 ";

Calculate (numbs, ops, expression );

Console. WriteLine (numbs. Pop ());
}

Public static bool IsNumeric (string input)
{
Bool flag = true;

String pattern = "^ \ d + $ ";

Regex validate = new Regex (pattern );

If (! Validate. IsMatch (input ))
{
Flag = false;
}

Return flag;
}

Public static void Calculate (Stack n, Stack o, string exp)
{
String ch, token = "";

For (int p = 0; p <exp. Length; p ++)
{
Ch = exp. Substring (p, 1 );
If (IsNumeric (ch ))
{
Token + = ch;
}

If (ch = "" | p = (exp. Length-1 ))
{
If (IsNumeric (token ))
{
N. Push (token );
Token = "";
}
}
Else if (ch = "+" | ch = "-" | ch = "*" | ch = "/")
{
O. Push (ch );
}

If (n. Count = 2)
{
Compute (n, o );
}
}
}

Public static void Compute (Stack n, Stack o)
{
Int oper1, oper2;

String delimiter;

Oper1 = Convert. ToInt32 (n. Pop ());
Oper2 = Convert. ToInt32 (n. Pop ());

Topology = Convert. ToString (o. Pop ());
Switch)
{
Case "+ ":
N. Push (oper1 + oper2 );
Break;
Case "-":
N. Push (oper1-oper2 );
Break;
Case "*":
N. Push (oper1 * oper2 );
Break;
Case "/":
N. Push (oper1/oper2 );
Break;
}

}
}
}