stuck in an infinite loop don't know what im doing wrong.


#include <iostream> // have to have for output

#include <string>

#include <iomanip>

#include <limits>

#include <sstream>

using namespace std;
int main() // the main function
{
float length; // stores lengthint=0
float width;// stores width
float depth; //stores depth
float gallon; //stores the answer in gallons
cout<< "welcome to the Fish Tank calculator"" " <<'\n';//welcome text
do
{
cout << "enter the length of your fish tank in inches, numbers only" <<'\n';
cin >> length;
}

while (!isdigit(length));
cout << "Not a number " << endl;