Thread: Dynamic Array called by function, help needed

I am having trouble creating a code that ask the user to input the size of an array and that array will display random characters of the alphabet. Before I added the function it worked perfectly but after I get couple of errors because I am kind of new when it comes to dynamic functions and arrays. I added pics of it.

We are in the year 2017 now. There is no more need to use dynamic arrays, we have strings and vectors and....
Have a look at this demo using modern C++.

Code:

#include <iostream>
#include <string>

std::string randomString(const size_t size)
{
  const std::string chars("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");

  std::string retval(size, ' ');

  for (size_t i = 0; i < size; i++)
  {
    retval[i] = static_cast<char>(chars[rand() % chars.size()]);
  }
  return retval;
}

int main()
{
  std::cout << "Enter the number of characters the string should contain: ";
  size_t size;
  std::cin >> size;
  std::string s = randomString(size);
  std::cout << "Your string: " << s << "\n\n";
  return 0;
}

Enter the number of characters the string should contain: 17
Your string: PhQGHuMEAyLnLFDxF

Code:

  for (size_t i = 0; i < size; i++)
  {
    retval[i] = static_cast<char>(chars[rand() % chars.size()]);
  }

Why the unnecessary static_cast?

And why not just use a ranged based loop, if you want to show "modern C++"?

Code:

    for(auto& itr : retval)
        itr = chars[rand() % chars.size()];

Yes , the static_cast was not necessary. I just hacked it together in 2-3 minutes without much thinking.

I didn't use the ranged based loop because the for loop is easier to understand for a beginner.

Thanks and I used the dynamic array because my assignment told me to use it.

Is it working now?