#include <stdio.h>

#define N 100

void sum_right_neighbour(int v[N], int n)
{
    int i;

    for (i = 0; i < n - 1; i++) {
        v[i] += v[i+1];
    }
}

void print_vector(int v[N], int n)
{
    int i;

    for (i = 0; i < n; i++) {
	printf("%d ", v[i]);
    }
    printf("\n");
}

int main(void)
{
    int v[N] = {1, 2, 3, 4, 5};

    print_vector(v, 5);
    sum_right_neighbour(v, 5);
    print_vector(v, 5);
    
    return 0;
}