C++ 的第一天

Question

I need to ask for the user's Initials and have it return their input. If they input any int I need it to loop back and ask them again.

int main()
{
    // Program 1-1

    std::cout<<"Hello, can you please enter your initials?\n";
    char initials[50];
    std::cin.getline(initials, 50);

    while (std::cin != int)
    {
        std::cout << "Thank you. " << initials << std::endl;
    }
    else (std::cin.fail())
    {
        std::cin.clear();
    }
}

Answer 1

#include <cctype>
#include <iostream>
#include <string>

int main() {
  std::string tmp;

  bool bogusInput;
  do {
    std::cout << "Initials: ";
    std::getline(std::cin, tmp);

    bogusInput = false;

    for (auto i : tmp) {
      if (std::isdigit(i)) {
        bogusInput = true;
        break;
      }
    }

    if (bogusInput) {
      std::cout << "Are you Elon's son? Please enter letters only.\n";
    }
  } while (bogusInput);

  std::cout << "Thank you, " << tmp << ".\n";

  return 0;
}

This code does the job you describe. I chose a do/while loop since I always need to get initials at least one time.

The variable bogusInput is a flag that I use to know if something hasn't worked out properly. It is declared outside of the loop for the sake of the while condition. It is always reset before performing the check, this allows the case of multiple attempts to work.

Finally, "valid" input gets us out of the loop and we say thank you and end.