StackLinked<DataType>::StackLinked(const StackLinked& other){
if(this != other){
while(!other->isEmpty()){
this->push(other->pop());
}
}
}
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;
}