Maximum 69 Number.cpp

class Solution {
public:
    int maximum69Number (int num) {
        string s=to_string(num);
        for(int i=0;i<s.size();i++){
            if(s[i]=='6'){
                 s[i]='9';
                break;
            }
               
        }
        num=stoi(s);
        return num;
    }
};