#include <iostream>
#include <iomanip>
#include <cctype>
using namespace std;
int main()
{
    int count[26] = {0};
    string input;
    cout << "Enter a message: ";
    getline(cin, input);
    for(int i = 0; i < input.length(); i++)
    {
        if(isalpha(input[i])) // A-Za-z
        {
            int j;
            if(isupper(input[i])) {
                j = input[i] - 'A';
            }
            else {
                j = input[i] - 'a';
            }
            count[j]++;
        }
    }
    // Show the counts:
    for(int i = 0; i < 26; i++)
    {
        char letter = i + 65;
        cout << setw(5) << letter
             << setw(3) << count[i];
        if(i%5 == 4) {
            cout << endl;
        }
    }
    cout << endl;
    return 0;
}

// Dealing with errors in 'cin'.
// Here's an example that can detect if reading a
// numeric value fails. You have to tell cin to
// clear its error condition and then ignore the
// previous input. It's a little awkward.
#include <iostream>
using namespace std;
int main()
{
    int num;
    cout << "Enter a number: ";
    while(!(cin >> num))
    {
        cout << "ERROR: try again: ";
        cin.clear(); // reset error state
        cin.ignore();// must clear *then* ignore
    }
    cout << "You entered " << num << endl;
    return 0;
}