Competitive Programming

#include <bits/stdc++.h>
using namespace std;
int main() {
    int testcase;
    char s[1024];
    double gmol[128];
    gmol['C'] = 12.01;
    gmol['H'] = 1.008;
    gmol['O'] = 16.00;
    gmol['N'] = 14.01;
    cin>>testcase;
    while (testcase--) {
        scanf("%s", s);
        double ret = 0;
        for (int i = 0; i < strlen(s); ) {
            int ele = s[i], num = 0;
            i++;
            while (s[i] >= '0' && s[i] <= '9')
                num = num * 10 + s[i] - '0', i++;
            if (num == 0)
                num = 1;
            ret += gmol[ele] * num;
        }
        printf("%.3lf\n", ret);
    }
    return 0;
}