myString.cpp

/****************************************************************************
  FileName     [ myString.cpp ]
  PackageName  [ util ]
  Synopsis     [ Customized string processing functions ]
  Author       [ Chung-Yang (Ric) Huang ]
  Copyright    [ Copyleft(c) 2007-present LaDs(III), GIEE, NTU, Taiwan ]
****************************************************************************/
#include <string>
#include <ctype.h>

using namespace std;

// Convert string "str" to integer "num". Return false if str does not appear
// to be a number
bool
myStr2Int(const string& str, int& num)
{
   num = 0;
   size_t i = 0;
   int sign = 1;
   if (str[0] == '-') { sign = -1; i = 1; }
   bool valid = false;
   for (; i < str.size(); ++i) {
      if (isdigit(str[i])) {
         num *= 10;
         num += int(str[i] - '0');
         valid = true;
      }
      else return false;
   }
   num *= sign;
   return valid;
}