Dev - C++ - algoritmo que nos diga cuántas veces aparece cada letra del alfabeto inglés

#include <iostream>

#include <cctype> // toupper

using namespace std;

int main()

{

    char caracter;

    int a = 0, b = 0, c = 0, d = 0, e = 0, f = 0, g = 0;

    int h = 0, i = 0, j = 0, k = 0, l = 0, m = 0, n = 0;

    int o = 0, p = 0, q = 0, r = 0, s = 0, t = 0, u = 0;

    int v = 0, w = 0, x = 0, y = 0, z = 0;

    cout << "\nintroduzca un texto, # para terminar: ";

    do {

        cin >> caracter;

        caracter = toupper(caracter);

        switch (caracter) {

            case 'A': a++; break;

            case 'B': b++; break;

            case 'C': c++; break;

            case 'D': d++; break;

            case 'E': e++; break;

            case 'F': f++; break;

            case 'G': g++; break;

            case 'H': h++; break;

            case 'I': i++; break;

            case 'J': j++; break;

            case 'K': k++; break;

            case 'L': l++; break;

            case 'M': m++; break;

            case 'N': n++; break;

            case 'O': o++; break;

            case 'P': p++; break;

            case 'Q': q++; break;

            case 'R': r++; break;

            case 'S': s++; break;

            case 'T': t++; break;

            case 'U': u++; break;

            case 'V': v++; break;

            case 'W': w++; break;

            case 'X': x++; break;

            case 'Y': y++; break;

            case 'Z': z++; break;

            default: break;

        }

    } while(caracter != '#');

    cout << "\nLetras 'A': " << a

         << "\nLetras 'B': " << b

         << "\nLetras 'C': " << c

         << "\nLetras 'D': " << d

         << "\nLetras 'E': " << e

         << "\nLetras 'F': " << f

         << "\nLetras 'G': " << g

         << "\nLetras 'H': " << h

         << "\nLetras 'I': " << i

         << "\nLetras 'J': " << j

         << "\nLetras 'K': " << k

         << "\nLetras 'L': " << l

         << "\nLetras 'M': " << m

         << "\nLetras 'N': " << n

         << "\nLetras 'O': " << o

         << "\nLetras 'P': " << p

         << "\nLetras 'Q': " << q

         << "\nLetras 'R': " << r

         << "\nLetras 'S': " << s

         << "\nLetras 'T': " << t

         << "\nLetras 'U': " << u

         << "\nLetras 'V': " << v

         << "\nLetras 'W': " << w

         << "\nLetras 'X': " << x

         << "\nLetras 'Y': " << y

         << "\nLetras 'Z': " << z;

    cout << endl;

    return 0;

}

int v[26] = {0};

#include <iostream>

#include <vector>

#include <cstdlib>

#include <cctype>

#include <cstddef>

using namespace std;

void print(vector<int> const &);

void read_lines_char_by_char();

int main() {

  read_lines_char_by_char();

  return EXIT_SUCCESS;

}

void read_lines_char_by_char() {

  vector<int> alphabet(26, 0);

  const char ending_char= '#';

  const char A = 'A';

  const char Z = 'Z';

  char read_char = '\0';

  do {

    cin >> read_char;

    read_char = toupper(read_char);

    if(A <= read_char && read_char <= Z)

      alphabet[read_char - A]++;

  }while (ending_char != read_char);

  print(alphabet);

}

void print(vector<int> const &input) {

  for (size_t i = 0 ; i < input.size() ; i++) {

    cout << (char)(i + 'A') <<": "<< input.at(i) << endl;

  }

}