balanced.cpp

#include "balanced.h"

// Returns true if the parenthesis,
//  square brackets, and curly braces
//  in text are balanced
bool isBalanced(const std::string &text){

  char c;
  char fromStack;
  std::stack<char> unmatched;

  for(int i=0; i<text.size(); i++){
    c = text[i];
    switch(c){
    case '[':
      unmatched.push(c);
      break;
    case '{':
      unmatched.push(c);
      break;
    case '(':
      unmatched.push(c);
      break;
    case ']':
      if(unmatched.empty() || unmatched.top() != '['){
        return false;
      }
      unmatched.pop();
      break;
    case '}':
      if(unmatched.empty() || unmatched.top() != '{'){
        return false;
      }
      unmatched.pop();
      break;
    case ')':
      if(unmatched.empty() || unmatched.top() != '('){
        return false;
      }
      unmatched.pop();
      break;

    }
  }
  if(!unmatched.empty())
  {
    return false; 
  }
  return true;
}