错误:表达式必须具有整数或枚举类型 [英] Error : Expression must have integral or enum type

问题描述

在Vincenty直接公式中，有一个表达式

In a Vincenty Direct Formula, there is an expression

lon2 = (lon1.toRad()+L+3*Math.PI) % (2*Math.PI) - Math.PI; 

/* Where lon2, lon1 is in degrees,L in double, Math.PI(Predefined value for PI) is a constant double */

但是会出现一个错误消息:表达式必须具有整数或枚举类型"，并且还表明％的左侧具有双精度型，而右侧具有恒定的双精度型.但这就是公式.我该如何摆脱呢?

But there is an error that says: "Expression must have integral or enum type" and also shows that the left hand side of % has a double and right hand side has a constant double. But that is the formula. How do I get rid of this?

推荐答案

那么?双倍％双倍是Double，不是吗?因此，如果期望lon2的整数，除非将其显式转换为整数，否则它将抱怨.

So? A Double % a Double gives a Double, doesn''t it? So if it expects an integer for lon2 it will complain unless you cast it to an integer explicitly.

模运算符%不能与浮点操作数一起使用.使用fmod()函数计算浮点值的余数.

The modulo operator % can''t be used with floating point operands. Use the fmod() function to calculate the remainder for floating point values.

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