missing ';' before '{'
#include <stdio.h>
int main(){
double sum=0.0;
int i=1;
while(i<=100,i %2== 1){
sum=sum + 1.0/i;
i++;}
else(i<=100,i %2=! 1){
sum=sum - 1.0/i;
i++;}
printf("%lf\n",sum);
return 0;
}