public char findTheDifference(String s, String t) { char c = 0; for (int i = 0; i < s.length(); ++i) { c ^= s.charAt(i); } for (int i = 0; i < t.length(); ++i) { c ^= t.charAt(i); } return c;}s.charAt(i) 取s里的第i个字符char a='1';//定义一个字符String b="dadsa";//定义一个字符串
