Exemplo n.º 1
0
StackLinked<DataType>::StackLinked(const StackLinked& other){
	if(this != other){
		while(!other->isEmpty()){
			this->push(other->pop());
		}
	}
}
Exemplo n.º 2
0
double calculatePostfixExpression(char* expression) {
  // variables
  int ndx = 0;
  char current_char = char(4);
  StackLinked<double> C;
  StackLinked<double>* contents = new StackLinked<double>;
  double operand1 = -8.88;    // arbitrary values for garbage
  double operand2 = -8.88;    // clearing and debugging
  double result = -8.88;

  // calculate the expression
  for(ndx = 0; ndx < MAX_EXPRESSION; ndx++) {
    // extract item from expression
    current_char = expression[ndx];

    // take appropriate action
    switch(current_char) {
      case '\0':
        // stop processing when \0 is encountered 
        ndx = MAX_EXPRESSION;   // this will break loop
        break;

      // ignore whitespace
      case ' ':
        // do nothing
        break;

      // store numbers in stack
      case '0':
      case '1':
      case '2':
      case '3':
      case '4':
      case '5':
      case '6':
      case '7':
      case '8':
      case '9':
        contents->push( double(current_char - '0') );
        break;

      // perform specified operations
      case '+':
         // gather operands
         operand2 = contents->pop();
         operand1 = contents->pop();

         // do the math
         result = operand1 + operand2;

         // store the result
         contents->push(result);
         break;

      case '-':
         // gather operands
         operand2 = contents->pop();
         operand1 = contents->pop();

         // do the math
         result = operand1 - operand2;

         // store the result
         contents->push(result);
         break;

      case '*':
         // gather operands
         operand2 = contents->pop();
         operand1 = contents->pop();

         // do the math
         result = operand1 * operand2;

         // store the result
         contents->push(result);
         break;

      case '/':
         // gather operands
         operand2 = contents->pop();
         operand1 = contents->pop();

         // do the math
         result = operand1 / operand2;

         // store the result
         contents->push(result);
         break;

      default:
        // ignore all other characters, i.e. do nothing
        break;
    }
  }

  // save the result before returning dynamic memory
  result = contents->pop();
  
  // return dynamic memory
  delete contents;
  contents = NULL;

  // return the result
  return result;
}