java - java 帮助中的命令行参数

Question

我想使用命令行参数来获取用户输入，而不是使用增强的 for 循环来求和。

这是错误:

线程“main”中的异常 java.lang.Error: Unresolved 编译问题: 类型不匹配:无法从 double 转换为 int

public class EnhanceForLoop {


public static void main(String[] args) {
    // TODO Auto-generated method stub

    if(args.length !=5)
        System.out.println(" please enter no more than 4 numbers");
    else
    {

    double sum; 
    double arrayLength = Double.parseDouble(args[0]);
    double [] myArray = new double [ arrayLength ];

    double value = Double.parseDouble((args[1]));
    double counter = Double.parseDouble((args[2]));


    for(double num: myArray)
      sum += num;


    System.out.printf("The sum is %f ", sum);

    }

}

}

目前情况如下:

公共(public)类 EnhanceForLoop {

public static void main(String[] args) {
    // TODO Auto-generated method stub

    if(args.length !=5)
        System.out.println(" please enter no more than 4 numbers");
    else
    {

    double sum = 0.0; 

    int arrayLength = Integer.parseInt(args[0]);
    double [] myArray = new double [ arrayLength ];

    double num1 = Double.parseDouble((args[1]));
    double num2 = Double.parseDouble((args[2]));
    double num3 = Double.parseDouble((args[3]));
    double num4 = Double.parseDouble((args[4]));
    double num5 = Double.parseDouble((args[5]));


    for(double num: myArray)
      sum += num;


    System.out.printf("The sum is %f ", sum);

    }

}

---

这里是答案:

公共(public)类 EnhanceForLoop {

public static void main(String[] args) {
    // TODO Auto-generated method stub

    if(args.length !=5)
        System.out.println(" please enter no more than 4 numbers");
    else
    {

    double sum = 0.0; 

    int arrayLength = Integer.parseInt(args[0]);
    double [] myArray = new double [ arrayLength ];

    double num1 = Double.parseDouble((args[1]));
    double num2 = Double.parseDouble((args[2]));
    double num3 = Double.parseDouble((args[3]));
    double num4 = Double.parseDouble((args[4]));



    for(String s: args){
        sum += Double.parseDouble(s);
    }
      System.out.println("Sum: "+sum);
    }




}

---

Answer 1

arrayLength 必须是整数。因此

int arrayLength = Integer.parseInt(args[0]);
double [] myArray = new double [ arrayLength ];