java 不兼容的类型：从 double 到 int 的可能有损转换
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Incompatible types: possible lossy conversion from double to int
提问by Sublīmis
Help? I don't know why I am getting this error. I am getting at in line 39:
帮助？我不知道为什么我会收到此错误。我在第 39 行：
term[1] = differentiate(Coeff[1], exponent[1]);
How can I fix this issue?
我该如何解决这个问题？
Full code listing:
完整代码清单：
public class Calcprog {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int numTerms = 7;
double[] Coeff = new double[6];
double[] exponent = new double[6];
String[] term = new String[6];
System.out.println("Enter the number of terms in your polynomial:");
numTerms = input.nextInt();
while (numTerms > 6) {
if (numTerms > 6) {
System.out.println("Please limit the number of terms to six.");
System.out.println("Enter the number of terms in your polynomial:");
numTerms = input.nextInt();
}
}
for (int i = 1; i < numTerms + 1; i++) {
System.out.println("Please enter the coefficient of term #" + i + " in decimal form:");
Coeff[i] = input.nextDouble();
System.out.println("Please enter the exponent of term #" + i + " in decimal form:");
exponent[i] = input.nextDouble();
}
term[1] = differentiate(Coeff[1], exponent[1]);
}
public String differentiate(int co, int exp) {
double newco, newexp;
String derivative;
newexp = exp - 1;
newco = co * exp;
derivative = Double.toString(newco) + "x" + Double.toString(newexp);
return derivative;
}
}
回答by Eran
You are trying to pass double arguments to a method that accepts ints, which requires a casting that may result in loss of information.
您正在尝试将双参数传递给接受整数的方法，这需要可能导致信息丢失的强制转换。
You can make it work by an explicit cast :
您可以通过显式转换使其工作：
term[1] = differentiate((int)Coeff[1], (int)exponent[1]);
Or you can change your differentiatemethod to accept double arguments, which would probably make more sense :
或者您可以更改您的differentiate方法以接受双参数，这可能更有意义：
public String differentiate(double co, double exp)
回答by Rafael Reis
your method is not static, and you calling in the main which is static, remember a non static method can be access direct in a static method, you have to create an instance of the class to access that method, and also the parameter you are passing is doubleand not int. Your method should be like that public static String differentiate(double co, double exp){
你的方法不是静态的，你调用的是静态的 main，记住一个非静态方法可以直接在静态方法中访问，你必须创建一个类的实例来访问该方法，以及你的参数路过是double与不是int。你的方法应该是这样的public static String differentiate(double co, double exp){
回答by René Winkler
change the argument types of the differentiate method to double. This should then look as follows
将差异方法的参数类型更改为双精度。这应该如下所示
public String differentiate(double co, double exp){
...
}
