How to make cin take only numbers

Question

Here is the code

double enter_number()
{
  double number;
  while(1)
  {

        cin>>number;
        if(cin.fail())
        {
            cin.clear()         


        

Answer 1

I would use std::getline and std::string to read the whole line and then only break out of the loop when you can convert the entire line to a double.

#include 
#include 

int main()
{
    std::string line;
    double d;
    while (std::getline(std::cin, line))
    {
        std::stringstream ss(line);
        if (ss >> d)
        {
            if (ss.eof())
            {   // Success
                break;
            }
        }
        std::cout << "Error!" << std::endl;
    }
    std::cout << "Finally: " << d << std::endl;
}