Check if Word Equals Summation of Two Words.cpp

class Solution {
public:
    bool isSumEqual(string firstWord, string secondWord, string targetWord) {
        int first=0,second=0,target=0;
        for(int i=0;i<firstWord.size();i++)
            first=first*10 + (firstWord[i]-'a');
        
        for(int i=0;i<secondWord.size();i++)
            second=second*10 +(secondWord[i]-'a');
        
        for(int i=0;i<targetWord.size();i++)
            target=target*10 +(targetWord[i]-'a');
        
        
        return first+second == target;
    }
};