说明：  printf()函数是式样化输出函数, 一般用于向准则输出设备按规定式样输出消息。正在编写步骤时经常会用到此函数。printf()函数的挪用式样为: printf("<式样化字符串>"，<参量表>)；
(The printf () function is a stylized output function, which is generally used to output messages to a standard output device in a prescribed pattern. You are often used to this function when you are writing the steps. The misappropriation of the printf () function is as follows: Printf ("< stylized string >", < parametric Table >);)