@各位大佬，帮我看看打字员这题哪里错了

#include <iostream>
#include <string>
using namespace std;



int main() {



    int f[105], d, sum = 0;
    cin >> d;
    string a;



    for (int i = 1; i <= d; i++) {
        cin >> a;
        sum = 0;
        sum = a.length();
        if (a[0] >= 'A' && a[0] <= 'Z') {
            sum++;
        }


        for (int j = 0; j <= a.length() - 2; j++) {
            if (a[j] >= 'a' && a[j] <= 'z' && a[j + 1] >= 'A' && a[j + 1] <= 'Z' ||
                a[j] >= 'A' && a[j] <= 'Z' && a[j + 1] >= 'a' && a[j + 1] <= 'z') {
                sum++;
            }
        }
        f[i] = sum;



    }


    for (int i = 1; i <= d; i++) {
        cout << f[i] << endl;
    }



    return 0;
}