Hey everybody first-time post. The issue I am running into is currently I am creating a token for each character which is fine, but when I have an expression like (10 2) it should equal 12, not 2. I have tried adding in a delimiter as shown commented out, but I do not quite understand exactly how a StringTokenizer works. From my understanding, I see two different ways of solving this issue. First, use the StringTokenizer to split the expression for operators( -*/) and values. Second, ive considered changing the else statement. I'm posting here because I have been trying to wrap my mind around this and I could use a push in the right direction.

// shuntingYard algorithm to convert fromc infix to postfix
public String shuntingYard(String infix) {
StringBuilder output = new StringBuilder();
Stack<String> stack = new Stack<String>();

//String DELIMITERS = "\" -*/^\"";

//this.tokenizer = new StringTokenizer(RPN, DELIMITERS, true);
for (String token : infix.split("")) {
//operator
if (Operator.operators.containsKey(token)) {
while ( ! stack.isEmpty() && isHigherPrec(token, stack.peek())) {
output.append(stack.pop()).append(' ');
}
stack.push(token);
}
//left parenthesis
else if (token.equals("(")) {
stack.push(token);
}
//right parenthesis
else if (token.equals(")")) {
while ( ! stack.peek().equals("(")) {
output.append(stack.pop()).append(' ');
}
stack.pop();
}
//digit
else {
// Find a way to check for multidigits
output.append(token).append(' ');
}
}
while ( ! stack.isEmpty()) {
output.append(stack.pop()).append(' ');
}
return output.toString();
}