#include <iostream>
//#include <cstdlib>
#include <ctime>
using namespace std;
 
const int NUMBER_OF_LETTERS = 26;
const int NUMBER_OF_RANDOM_LETTERS = 100;
void createArray(char []);
void displayArray(const char []);
void countLetters(const char [], int []);
void displayCounts(const int []);
 
int main()
{
  char chars[NUMBER_OF_RANDOM_LETTERS];
  createArray(chars);
  cout << \"The lowercase letters are:\" << endl;
  displayArray(chars);
  int counts[NUMBER_OF_LETTERS];
  countLetters(chars, counts);
  cout << \"\\nThe occurrences of each letter are:\" << endl;
  displayCounts(counts);
 
  return 0;
}
 
void createArray(char chars[])
{
  srand((unsigned int)time(0));
  for (int i = 0; i < NUMBER_OF_RANDOM_LETTERS; i++)
  {
    chars[i] = static_cast<char>(\'a\' + rand() % (\'z\' - \'a\' + 1));
  }
}
 
void displayArray(const char chars[])
{
  for (int i = 0; i < NUMBER_OF_RANDOM_LETTERS; i++)
  {
    if ((i + 1) % 20 == 0)
      cout << chars[i] << \" \" << endl;
    else
      cout << chars[i] << \" \";
  }
}
 
void countLetters(const char chars[], int counts[])
{
  for (int i = 0; i < NUMBER_OF_LETTERS; i++)
    counts[i] = 0;
  for (int i = 0; i < NUMBER_OF_RANDOM_LETTERS; i++)
    counts[chars[i] - \'a\']++; //经典
}
 
void displayCounts(const int counts[])
{
  for (int i = 0; i < NUMBER_OF_LETTERS; i++)
  {
    if ((i + 1) % 10 == 0)
      cout << counts[i] << \" \" << static_cast<char>(i + \'a\') << endl;
    else
      cout << counts[i] << \" \" << static_cast<char>(i + \'a\') << \" \";
  }
  cout << endl;
}