我该如何处理这个递归函数的基本情况？我的基本情况导致输出为零

Question

''' Returns number of pennies if pennies are doubled num_days times'''
def double_pennies(num_pennies, num_days):
    total_pennies = 0

    if num_days == 0:
        return total_pennies

    else:
        total_pennies = double_pennies((num_pennies * 2), (num_days - 1));

    return total_pennies

''' Program computes pennies if you have 1 penny today,'''
''' 2 pennies after one day, 4 after two days, and so on'''
starting_pennies = 1
user_days = 10

print('Number of pennies after', user_days, 'days: ', end="")
print(double_pennies(starting_pennies, user_days))

原文由 Umubale 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

这个基本案例对我有用

if num_days == 0:
    total_pennies = num_pennies

原文由 luckyguy73 发布，翻译遵循 CC BY-SA 4.0 许可协议