sum & avg for

#include<stdio.h>
int main()
{
    double avg,c,d,sum=0,i;
    for(i=0;i<=100;i++)
    {
        sum=sum+i;
        i++;
    }
    avg=sum/100;
    printf("%.2lf\n",sum);
    printf("%.2lf\n",avg);
    return 0;
}