1768. 交替合并字符串

题目链接：1768. 交替合并字符串

代码如下：

class Solution 
{
public:
    string mergeAlternately(string word1, string word2) 
    {
        string res="";
        int i=0;
        for(;i<word1.size()&&i<word2.size();i++)
        {
            res+=word1[i];
            res+=word2[i];
        }

        for(;i<word1.size();i++)    {res+=word1[i];}
        for(;i<word2.size();i++)    {res+=word2[i];}
        return res;
    }
};