Press q to quit outputs incorrect math - c

Question

I am trying to use "Press 'q' to quit" functionality to exit a do...while loop for calculating the average of a series of user-defined integers. Following several examples I was able to get the exit value to work but it is being included as part of calculating the average.
Example:
quixote#willow:~$ gcc sentinel-borked.c -o sentinel-borked
sentinel-borked.c: In function 'main':
sentinel-borked.c:22:13: warning: assignment makes integer from pointer without a cast [-Wint-conversion]
sum = sum + value;
^
quixote#willow:~$ ./sentinel-borked
Enter an answer string or q to quit: 1
Enter an answer string or q to quit: 1
Enter an answer string or q to quit: q
Count is: 3
Average is: 214197589.333333
quixote#willow:~$
I know that the "q" is being treated as an integer, but I'm not sure how to re-write my code to escape it. :(
The simplest workaround that I can think of is to prompt the user for an end point (i.e. "how many integers are you averaging?") and use that, but I would really like to figure this out.
Here is the code I have so far.
#include <stdio.h>
#include <string.h>
int main ()
{
/* variable definition: */
int count, sum;
double avg;
char *value;
/* Initialize */
count = 0;
sum = 0;
avg = 0.0;
do {
// Loop through to input values
printf("\nEnter an answer string or q to quit: ");
fgets(value, 10, stdin);
if (value >= 0){
sum = sum + value;
count = count + 1;
}
else {
printf("\nValue must be positive");
}
} while (value[0] != 'q');
// Calculate avg. Need to type cast since two integers will yield an integer
printf("\nCount is: %d", count);
avg = (double) sum/count;
printf("\nAverage is: %lf\n", avg);
return 0;
}
EDIT: Replaced screenshot with plain-text inside of a code block. Original image still located at: https://i.stack.imgur.com/qza1N.png

Answer 1

Try this:
#include <stdio.h>
#include <string.h>
int main ()
{
/* variable definition: */
int count, sum;
double avg=0;
char value[10]="";//make value an array or allocate memory for it using malloc and also null initiate it
/* Initialize */
count = 0;
sum = 0;
avg = 0.0;
fgets(value,10,stdin);
if(value[strlen(value)-1]=='\n'){//if the user enters a string less than 10 chars a newline will also be stored inside the value array
value[strlen(value)-1]='\0';//you need to remove that \n and replace it with null
}
else{
while((getchar())!='\n');//just removing any extra chars left(when the user enters a string greater than 10 chars)
}
while(value[0]!='q'){//beware it will only check for the first char of the array to be q, anything else will still proceed the loop
sum+=strtol(value,NULL,10);//use this to convert integers inside the array to long ints(many other ways exists)
count++;
fgets(value,10,stdin);//overwrite value each time to get input
if(value[strlen(value)-1]=='\n'){
value[strlen(value)-1]='\0';
}
else{
while((getchar())!='\n');
}
}
// Calculate avg. Need to type cast since two integers will yield an integer
printf("\nCount is: %d", count);
if(count==0){
printf("\nAverage is: %lf\n", avg);
}
else{
avg = (double) sum/count;
printf("\nAverage is: %lf\n", avg);
}
return 0;
}