Functions can either return some value or object to your main program (like the current time), or they can perform some action (like setting the time) without returning a value.
Functions can either return some value or object to your main program (like the current time), or they can perform some action (like setting the time) without returning a value.
函数可以或者返回一些值或对象到你的主程序（好比现在），或者他们能够执行一些操作（比方说设置时间）但不返回任何值。