2678. Number of Senior Citizens

You are given a 0-indexed array of strings details. Each element of details provides information about a given passenger compressed into a string of length 15. The system is such that:

• The first ten characters consist of the phone number of passengers.
• The next character denotes the gender of the person.
• The following two characters are used to indicate the age of the person.
• The last two characters determine the seat allotted to that person.

Return the number of passengers who are strictly more than 60 years old.

class Solution {
public:
    int countSeniors(vector<string>& details) {
        int res = 0;
        for(auto d : details) {
            int age = (d[11] - '0') * 10 + d[12] - '0';
            res += age > 60;
        }
        return res;
    }
};