Recursion Advnc camo. odd nmbr sum

#include<stdio.h>
int *s=0;
void odd_sum(int n)
{

    if(n%2==1)
    {
        s+=n;
    }
    else
    {
        n=n-1;
        s+=n;
    }
    if(n<0);
    {
        printf("Sum= %d\n",s);
        return;
    }
    odd_sum(n-2);
}
int main()
{
    int x;
    scanf("%d",&x);
    odd_sum(x);
}