Program terminates if anything enter other than a number is entered

I'm working though Programming: Principles and Practice using C++. And I can't get my program to accept a double then a string. It terminates as soon as I enter in a string.

If I enter any number i.e. 100 it works as expected, outputting the smallest so far and the largest.

If I enter 100m, 100 m, 100, m the program outputs the smallest so far and the largest but I can't get it to output the string unit "m".

I'm teaching myself so any input at all even if it isn't related to this question would be greatly appreciated.

Thank you

I have tried the val1 hitting enter then the string. I've tried https://github.com/bewuethr/stroustrup-ppp/blob/master/chapter04/chapter04_drill.cpp and I can't even get this program to run on netBeans I've added a general string "unit"

#include "std_lib_facilities.h"

int main ()
{

    double val1 = 0; // initialized
    double val1_conv = 0; //intialized
    double smaller = INFINITY; // initialized
    double larger = -INFINITY; // initialized

    vector<double> compare; // empty vector of doubles


    string unit = "";  // Added this to see if it would allow a string, I've also tried removing the = "" 
    string meter = "m";
    string centi = "cm";
    string foot = "ft";
    string inch = "in";

    cout << "Please input a value follow by unit (ie cm,m, in,ft), us | to stop" << endl; // put into

    while (cin >> val1 >> unit)   // cin "get from"
    {
        compare.push_back(val1);

        if (unit == "m") // Just trying to get the program to accept a string after an double
        {
            cout << val1 << unit;
        }

        if (val1 < smaller)
        {
            smaller = val1; // assignment giving a variable a new value
            cout << val1 << " is the smallest so far \n";
            compare.push_back(smaller);
        }

        if (val1 > larger)
        {
            larger = val1;   // assignment giving a variable a new value
            cout << val1 << " is the largest so far \n";
            compare.push_back(larger);
        }

    }
    return 0; // The book doesn't have us adding this line to everything but I tried it.
}

It acts like as if I didn't add any of the strings or unit to the val