sum_of_series_simple_code.c

#include<stdio.h>
int main(){
    int i,n,c=1,sum=0;
    scanf("%d",&n);
    for(i=1; i<(n/2)+2; i++,c+=2)
        i%2 ? sum += c : (sum -= c);
    printf("Sum = %d",sum);
    return 0;
}