Question

using System;

public class Newton_Ralphson
{
    public double compute(double x,int n,double[] P)            // x, degree, coefficients 
    {
        double pol = 0;
        for (int i = 0;i < n;i++)
        {
            for (int j = 1; j < n - i; j++)
                x *= x;
                pol += P[n - i] * x;
        }
        pol += P[0];
        return pol;
    }

public double[] secondary_Pol(int n, double[] P)            //slope
{
    double[] secP = new double[n - 1];
    for (int i = 0; i < n - 1; i++) 
        secP[i] = P[i + 1];
    return secP;
}

public double Main()
{
    Console.WriteLine("Estimate the solution for a nth degree polynomial!!! ");
    int n = 0;
    Console.WriteLine("Enter the degree of the polynomials! ");
    n = Int32.Parse(Console.ReadLine());
    double[] coefficients = new double[n+1];

    for(int i = 0;i < n+1;i++)
    {
        Console.WriteLine("Enter the coefficients ");
        Console.Write("coefficients of x to the power of {0}: ", n - i);         //decending coefficients 
        coefficients[n-i] = Convert.ToDouble(Console.ReadLine());
    }


    Console.WriteLine("Initial value is: ");
    double xint = Convert.ToDouble(Console.ReadLine());

    Console.WriteLine("How many times does the function go through? ");
    int precision = Convert.ToInt32(Console.ReadLine());
    double polyValue = 0;

    for (int j = 0; j < precision; j++)
    {
        polyValue = compute(xint, n, coefficients);                              //y0 in y = slope(x-x0) + y0
        double slope = compute(xint, n - 1, secondary_Pol(n, coefficients));
        xint = (-polyValue / slope) + xint;
    }
    Console.WriteLine(xint);
    Console.ReadLine();
    return 0;
}

}

当我在行中添加'static'时：public static double Main（）出现了另一个错误

错误CS0120：非静态字段，方法或属性'Newton_Ralphson.compute（double，int，double []）'

需要对象引用执行另外两个函数时出现

错误

Answer 1

请参阅C# entry point function

C＃应用程序，Main（）必须是入口点。

原因是因为这就是语言的设计者决定寻找什么作为您的计划的切入点。他们也可以使用完全不同的方法来查找入口点，例如使用元数据，或实例化对象你（这将需要一个无参数的构造函数）。另一个原因命名为void main（）是对来自用户的直观其他语言。

使用：

public class Newton_Ralphson
{
    public static double compute(double x, int n, double[] P) // x, degree, coefficients 
    {
        double pol = 0;
        for (int i = 0; i < n; i++)
        {
            for (int j = 1; j < n - i; j++)
                x *= x;
            pol += P[n - i]*x;
        }
        pol += P[0];
        return pol;
    }

    public static double[] secondary_Pol(int n, double[] P) //slope
    {
        double[] secP = new double[n - 1];
        for (int i = 0; i < n - 1; i++)
            secP[i] = P[i + 1];
        return secP;
    }

    public static void Main()
    {
        Console.WriteLine("Estimate the solution for a nth degree polynomial!!! ");
        int n = 0;
        Console.WriteLine("Enter the degree of the polynomials! ");
        n = Int32.Parse(Console.ReadLine());
        double[] coefficients = new double[n + 1];

        for (int i = 0; i < n + 1; i++)
        {
            Console.WriteLine("Enter the coefficients ");
            Console.Write("coefficients of x to the power of {0}: ", n - i); //decending coefficients 
            coefficients[n - i] = Convert.ToDouble(Console.ReadLine());
        }


        Console.WriteLine("Initial value is: ");
        double xint = Convert.ToDouble(Console.ReadLine());

        Console.WriteLine("How many times does the function go through? ");
        int precision = Convert.ToInt32(Console.ReadLine());
        double polyValue = 0;

        for (int j = 0; j < precision; j++)
        {
            polyValue = compute(xint, n, coefficients); //y0 in y = slope(x-x0) + y0
            double slope = compute(xint, n - 1, secondary_Pol(n, coefficients));
            xint = (-polyValue/slope) + xint;
        }
        Console.WriteLine(xint);
        Console.ReadLine();

    }
}

1 - 将public double Main()更改为public static void Main()

2 - 将public double[] secondary_Pol(int n, double[] P)更改为public static double[] secondary_Pol(int n, double[] P)

3 - 将public double compute(double x,int n,double[] P更改为public static double compute(double x, int n, double[] P)

Answer 2

向所有方法添加静态。如果不提供对象引用，则无法从静态方法调用非静态方法。作为替代方法，您可以创建类的实例并调用方法：

var c = new Newton_Ralphson();
c.compute();

Answer 3

在Visual Studio中创建新的C＃控制台应用程序将向您显示您通常需要的内容：

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args) // static with a void (or int) return type
        {
        }
    }
}

Main必须声明为static。

double Main绝对是一个问题。请参阅what a C# main method needs上较旧的MSDN文章 - 特别是void或int返回类型。

用于args的

Main string[]参数是可选的 - 即可以省略。请参阅上述MSDN文章以进行确认。

最后，将public添加到Main的声明很好但不必要，通常会跳过。

CS5001：exe不包含适用于入口点的静态“Main”方法

3 个答案: