Thread: While loop with multiple conditions.

My code's while loop has two values in it, a weight and a value. my sentinel value is "-1". I have tried to modify the conditions in the while loop to everything I can think of but I'm at a loss. When I enter my sentinel value in my standard input, it ends the loop but also factors in the sentinel value in the average. below is the code:

Code:

<#include <stdio.h>


int main (void) {
/* variable definition: */
   unsigned int counter;
   int count;
   double avg, value, weight, sum, sumw;
/* Initialize */
   counter =0;
   count = 0;
   sum = 0;
   sumw = 0;
   avg = 0.0;
// Loop through to input values
   while (value != -1) 
   {
      printf("Enter a value and its weight, -1 to end: ");
      // use %lf for double, %f for float
      scanf("%lf %lf", &value, &weight);
      printf("%.2lf (value) %.2lf (weight)\n", value, weight);
      if (weight != 0) {
         sumw = sumw + weight;
         sum = sum + value * weight;
         count = count + 1;
      }
      else {
         printf("Weight must be positive\n");
      } // end if weight ok
   } // end reading input values and weights
// Calculate avg if sumw is not 0
   avg = sum / sumw;
   printf("average is %lf\n " , avg );
   return 0;
} // end main>

and below is the output:

2 1 2 1 -1
stdout copy
Enter a value and its weight, -1 to end: 2.00 (value) 1.00 (weight)
Enter a value and its weight, -1 to end: 2.00 (value) 1.00 (weight)
Enter a value and its weight, -1 to end: -1.00 (value) 1.00 (weight)
average is 1.000000


I have tried to modify the code to read:

while (value && weight != -1)
While (value || weight != -1)
while (value, weight =! -1)
while (value != -1)
while (weight != -1)
While ((value) (weight) != -1)
while ((value), (weight) != -1)

none of these seem to work.

I had this code there simply because I attempted to change so many things in the code before posting here, I forgot to change it back. I am painfully new at this btw.

I set weight=0 under the initialization, I assumed this is what you meant. I also changed the "!=" back to ">". the results are still the same as before. instead of the program terminating after -1, the program is factoring in the -1 as a value and entering in a weight of 1 AND terminating the program, instead of just simply terminating it. If my input was 2 1 2 1 2 1-1, i should be getting the average = 2, instead I'm getting 1.25. Im sure there is an easy or obvious fix but I'm not sure how much longer I can butcher this code before figuring it out...