[Dev-C++] Basic C question: scanf

[Mary S. <ms...@in...>]

I've written a short program using Dev-C++ 4, but it does not execute as I
would expect. The code is as follows:

#include <stdio.h>

int main(int argc, char *argv[])
{
  double salary, fed_withhold, state_withhold;
  double salary_sum = 0, fed_sum = 0, state_sum = 0;

  printf("Enter salaries: ");
  while (scanf("%lf", &salary) == 1){
        fed_withhold = salary * .17;
        state_withhold = salary * .03;
        printf("salary: %.2f fed tax: %.2f state tax: %.2f\n",
                        salary, fed_withhold, state_withhold);
        salary_sum += salary;
        fed_sum += fed_withhold;
        state_sum += state_withhold;
  }
  printf("\nSalary total: %.2f Fed tax total: %.2f State tax total: %.2f\n",
                   salary_sum, fed_sum, state_sum);

  system("PAUSE");
  return 0;
}

When the program is run, the prompt "Enter salaries:" is printed. After
that, I enter a series of numbers, then press the Enter key. The printf in
the loop is executed for each number input, but then the program hangs. I
have to either interrupt the program (<cntrl>-z worked for this) or type in
alpha characters and hit Enter. At that point the printf after the while
loop is executed.

What have I got wrong or what is it that I don't understand?

Thanks,

Mary