tally.cpp

#include <vector>
#include <iostream>

int main()
{
    std::vector<std::pair<int, char>> tally(128);

    for (int i = 0; i < 128; i++) {
        tally[i].second = i;
    }

    char c;
    while (EOF != (c = fgetc(stdin))) {
        tally[c].first += 1;
    };

    std::sort(tally.begin(), tally.end());

    for (auto const& pair : tally) {
        if (pair.second) printf("%c %d\n", pair.second, pair.first);
    }
}