A Simple Question of Chemistry

#include<stdio.h>
int main()
{
int i, l;
 double a[100001];
double b[100001];
 l = 0;
 while(scanf("%lf", &a[l]) && a[l] != 999)
{
l++;
 }
for(i=1; a[i]!=999 && i<l; i++)
printf("%.2lf\n",a[i]-a[i-1]);
 printf("End of Output\n");
return 0;
}