Question

我是一个新手java的家伙试图让我的打印输出语句格式化十进制位置..我知道％。2f有效，但无论出于何种原因，当我尝试应用％.2f时，它就是炸弹....不知道该怎么做..有什么建议吗？提前谢谢！

credits = int 

raise = double

System.out.printf("An undergraduate resident student taking " + credits + " currently pays $" + "%,.2f",credtotal);

System.out.println("\n");

System.out.printf("with a increase in tuition of " + (trying to format here) raise + ", per credit will become " + raisecredund +  ", and an undergraduate resident taking " + credits +  " credits" + " will pay $" +"%,.2f",(credits*(raise*245.73))+ credtotal);;

Answer 1

 final String str1 = String.format("An undergraduate resident student taking %d currently pays $%.2f",credits, credtotal);

编辑：我没有注意到您使用的是printf。你很亲密：

 System.out.printf("An undergraduate resident student taking %d currently pays $%.2f", credits,credtotal);

使用第一个示例字符串，您可以内联提供格式化字符，然后为每个占位符提供参数。假设credtotal为双倍且知道credits为int，则上述将产生（分配相应的值）

An undergraduate resident student taking 1 currently pays $2.00

请参阅creating formatted strings section。

Answer 2

您似乎正在使用"%,.2f"逗号，我认为这不是合法的。 %.2f会将数字打印到2位小数。

如果你想在钱中加入逗号，你应该使用DecimalFormat
DecimalFormat formatter = new DecimalFormat("#,###.00");

打印输出语句格式化问题，双打java

2 个答案: