Characters Statistics

#include <iostream>

using namespace std;

int main(int argc, char const* argv[])
{
    int stat[256]{ 0 };
    char ch;

    while (cin.get(ch) && ch != '@') {
        stat[unsigned(ch)]++;
    }

    int alpha = 0;
    int numeric = 0;
    int others = 0;

    cout << "\n--- stat ---" << endl;

    for (unsigned ch = 0; ch < 256; ch++) {
        if (ch >= 'A' && ch <= 'Z') {
            alpha += stat[ch];
        } else if (ch >= 'a' && ch <= 'z') {
            alpha += stat[ch];
        } else if (ch >= '0' && ch <= '9') {
            numeric += stat[ch];
        } else {
            others += stat[ch];
        }
    }

    cout << "alpha\t" << alpha << endl
         << "numeric\t" << numeric << endl
         << "others\t" << others << endl;

    return 0;
}