(响应)我国现有人口为13亿，设年增长率为1 ，计算多少年后增加到20亿。并将结果输出在窗体上。将结果存入变量year中。使用do while ...loop语句完成程序。 -response) in China has a population of 1.3 billion, the annual growth rate of 1 , calculate how many years later increased to 2 billion. And the results output