Problem in Calculator implementation using Stack

[realahmed8]

I have build code for simple calculator but it don't accept more than 1 operand i.e.(22 not acceptable but 2 is acceptable), the code works only with parenthesis..
here is my code

import java.util.Stack;
 
    public static void main(String[] args) {
          char []a={'(','2','+','6',')'};
        
        System.out.println (evaluteExpression(a,5));
    }
    public static String evaluteExpression(char[]expression,int length){
        ArrayStack operator=new ArrayStack();
        Stack operand=new Stack();
        int op1value = 0,op2value = 0,finalresult = 0;
        char op = 0;
        int result;
        String op1,op2,resulttext="0";
        result=0;
         
    for(int i=0;i<length;i++){
         char c=expression[i];
 
         if(c!='('&&c!='+'&&c!='-'&&c!='*'&&c!='/'&&c!=')'&&c!='c'&&c!='s'&&c!='t')
         {
         
          String   b=String.valueOf(expression[i]);
          
                b=String.valueOf(expression[i]);
                
            operand.push(b);
 
        }
         else
         {
          switch (c){
                 case '(': case ' ':
                  break;
 
                  case '-':  case'+':  case'*':  case'/':
                      operator.push(c);
 
                      break;
 
              case'c':case's':case't':
                  operator.push(c);
                  i=i+2;
                  break;
 
                  case ')':
                      op=operator.pop();
                      op1= (String) operand.pop();
                      op1value=Integer.parseInt(op1);
  
                   if(op=='+'){
 
                    op2=(String)operand.pop();
                    op2value=Integer.parseInt(op2);
 
                   result=op1value + op2value;
                   resulttext=String.valueOf(result)  ;
                    operand.push(resulttext);
 
                   }
                   else if(op=='-'){
 
                    op2=(String)operand.pop();
                    op2value=Integer.parseInt(op2);
 
                     result=op1value-op2value;
                    resulttext=String.valueOf(result);
                   operand.push(resulttext);
                   }
                   else if(op=='*'){
 
                    op2=(String)operand.pop();
                    op2value=Integer.parseInt(op2);
 
                    result=op1value*op2value;
                    resulttext=String.valueOf(result);
                   operand.push(resulttext);
                   }
                   else if(op=='/'){
 
                    op2=(String)operand.pop();
                    op2value=Integer.parseInt(op2);
 
                    result=op2value/op1value;
                    resulttext=String.valueOf(result);
                   operand.push(resulttext);
                   }
                  
                   else if(op=='c'){
 
                        result= (int) Math.cos(op1value);
                       resulttext=String.valueOf(result);
                       operand.push(resulttext);
                   }
                      else if(op=='s'){
 
                        
 
                        op1value=Integer.parseInt(op1);
                        result= (int) Math.sin(op1value);
                       resulttext=String.valueOf(result);
                       operand.push(resulttext);
                  }
                      else if(op=='t'){
 
                    
 
                        op1value=Integer.parseInt(op1);
                        result= (int) Math.tan(op1value);
                       resulttext=String.valueOf(result);
                       operand.push(resulttext);
                  }
 
 
 
 
         }
 
 
 
    }
    }
 
 
 
   String a=(String) operand.pop();
 
    return a;
    }
}

public interface Stack1{
 
 
	public void push(char element);
	public char pop();
   public boolean isEmpty () ;
 
 
}

public class ArrayStack implements Stack1{
	public static final int CAPACITY = 1000;
	private int capacity;
	private char s[];
	private int top = -1;
 
	public ArrayStack(){
		this(CAPACITY);
	}
 
	public ArrayStack(int cap){
		capacity = cap;
		s = new char[capacity];
	}
 
 
 
 
 
	public void push(char element){
		s[++top] = element;
	}
 
 
 
	public char pop(){
		char elem;
		elem = s[top];
		s[top] = '\u0000';
     -- top;
		return elem;
	}
 
 
        public boolean isEmpty()
	{
		return(top < 0) ;
	}
 
    
}

also if you have any better methods please help me with it..
thanks..

[realahmed8]

so...........?