#include <string>
#include <iostream>
#include <cstddef>
#include <memory>
#include <utility>
 
std::unique_ptr<int[]> count_char(const std::string& s)
{
	// consider 128 ASCII decimal and their coresponding character codes
	std::unique_ptr<int[]> charASCIIArray = std::unique_ptr<int[]>(new int[128]{0});
	for (const auto& it : s)
	{
		if (('A' <= it && it <= 'Z') ||     // if char between (A,B,....,Z) or
			('a' <= it && it <= 'z'))       //         between (a,b,....,z)
			charASCIIArray[static_cast<int>(it)]++; // we count each corresponding array then
	}
	return std::move(charASCIIArray);
}
 
int main()
{
	std::string userinput = "random words WITH *- aLl";
 
	std::unique_ptr<int[]> charASCIIArray = count_char(userinput);
	for (std::size_t index = 0; index < 128; ++index)
		if (charASCIIArray[index] != 0)
			std::cout << "Letter " << static_cast<char>(index)  // convert back to char
			<< " occured " << charASCIIArray[index] << " times.\n";
 
	return 0;
}
 

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