# iteratively sum first n integers
def sum_iter(n):
    sum = 0
    for i in range(0,n+1):
        sum = sum + i

    return( sum )

print( sum_iter(10) )


# recursively sum first n integers
def sum_rec(n):
    if( n == 0 ):
        return(0)
    else:
        return n + sum_rec(n-1)
    
print( sum_rec(10) )