double number = 0;
int validCheck = 0;
char another = 'y';

while(another == 'y')
{
    cout<<"Please enter a number: ";
    validCheck = scanf("%lf", &number);

    while (validCheck !=1)
    {
        cout<<"Invalid input, please enter a number: ";
        validCheck = scanf("%lf", &number);
    }

int c;
do {
    c = getchar();
}while(c != 'n' && c != EOF);

#include <iostream>
#include <string>

using namespace std;

int main()
{
    double number = 0;
    int validCheck = 0;
    char another = 'y';
    string badinput;

    while(another == 'y')
    {
        cout<<"Please enter a number: ";


        while (!(cin >> number))
        {
            cin.clear();
            cin >> badinput;
            cout <<"Input " << badinput << " is invalid, please enter a number: ";
        }
    }

    return 0;
}