how do I validate user input as a double in C++?

by

Try this:

while (1) {
  if (cin >> x) {
      // valid number
      break;
  } else {
      // not a valid number
      cout << "Invalid Input! Please input a numerical value." << endl;
      cin.clear();
      while (cin.get() != '\n') ; // empty loop
  }
}

This basically clears the error state, then reads and discards everything that was entered on the previous line.

More Related Contents:

  1. Infinite loop with cin when typing string while a number is expected
  2. C++ Reading an unknown number of integers to cin and outputting the sum
  3. How to accept a string and an int using cin?
  4. c++ if specific words from string
  5. How do I flush the cin buffer?
  6. Using getline(cin, s) after cin [duplicate]
  7. cin and getline skipping input [duplicate]
  8. changing the delimiter for cin (c++)
  9. std::cin.getline( ) vs. std::cin
  10. Checking cin input stream produces an integer
  11. How do I convert a double into a string in C++?
  12. How to cin Space in c++?
  13. C++ decimal data types
  14. Integer validation for input
  15. Are all integer values perfectly represented as doubles? [duplicate]
  16. Hide user input on password prompt [duplicate]
  17. Correct way to use cin.fail()
  18. How to cin values into a vector
  19. How to read cin with whitespace up until a newline character?
  20. Portability of binary serialization of double/float type in C++
  21. cin input (input is an int) when I input a letter, instead of printing back incorrect once, it prints correct once then inc for the rest of the loop
  22. How to check if the input is a valid integer without any other chars?
  23. How to signify no more input for string ss in the loop while (cin >> ss)
  24. std::getline on std::cin
  25. Convert double to string C++? [duplicate]
  26. cin.getline() is skipping an input in C++ [duplicate]
  27. How Can I avoid char input for an int variable?
  28. How is “std::cin>>value” evaluated in a while loop?
  29. What’s the difference between getline and std::istream::operator>>()?
  30. narrowing conversion from unsigned to double

Leave a Comment