Sliding Window Sum

#include <stdio.h>

void sliding_window_sum(int arr[], int n, int k) {
    // Your logic here
    char flag;
    int i,sum;
    for(i=0;i<k;i++)
    { 
        sum += arr[i];
    }
    printf("%d", sum);
    // Slide the window
    for (i = k; i < n; i++) {
        sum += arr[i];       // add new element
        sum -= arr[i - k];   // remove old element
        printf(" %lld", sum);
    }
    
}

int main() {
    int n, k, arr[100];
    scanf("%d %d", &n, &k);
    for (int i = 0; i < n; i++) scanf("%d", &arr[i]);

    sliding_window_sum(arr, n, k);
    return 0;
}