题目描述：
Given two strings s and t which consist of only lowercase letters.
String t is generated by random shuffling string s and then add one more letter at a random position.
Find the letter that was added in t.
Example:
Input:
s = “abcd”
t = “abcde”
Output:
e
Explanation:
‘e’ is the letter that was added.
代码实现：
class Solution {
public:
char findTheDifference(string s, string t) {
char ch = t[0];
for(int i=1;i<t.size();i++){
ch ^= t[i];
}
for(int j=0;j<s.size();j++){
ch ^= s[j];
}
return ch;
}
};