货币的输入往往有一定的规则，像是不能以0开头，不能以标点开头，一个货币形式不能出现多个小数点等，此程序就是为在控制输入货币的形式-Enter the currency tend to have certain rules, such as can not be 0 at the beginning, should not to punctuation at the beginning of a monetary form should not appear in more than a decimal point and so on, this procedure is to control input in the form of currency