gistfile1.txt

#include <cs50.h>
#include <stdio.h>

// prompt user for change requirement

float main (void)
{
    float change;   
    printf("How much change do you want? \n");
    change = GetFloat();
    while (change < 0)
    {
    printf("Try again \n");
    printf("How much change do you want? "); 
    change = GetFloat(); 
    }
}