下面的代码该怎样改正。搞了半天都不懂。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace 函数对比大小值
{
    class Program
    {
        static void Main(string[] args)
        {
            int a = Convert.ToInt32(Console.ReadLine());
            int b = Convert.ToInt32(Console.ReadLine());
            int k =minnum(a, b); //就这里有问题
            Console.WriteLine(k);
        }

        int minnum(int a, int b)
        {
            int c = 0;
            if (a > b)
            {
                c =b;
            }
            else if (a < b)
            {
                c =a;
            }
            return c;
        }
    }
}

static int minnum(int a, int b)
        {
            int c = 0;
            if (a > b)
            {
                c = b;
            }
            else if (a < b)
            {
                c = a;
            }
            return c;
        }
       
         static void Main(string[] args)
        {
            int a = Convert.ToInt32(Console.ReadLine());
            int b = Convert.ToInt32(Console.ReadLine());
            int k = minnum(a, b);
            Console.WriteLine(k);
             Console.ReadKey();
        }       
        

或者

  int minnum(int a, int b)
        {
            int c = 0;
            if (a > b)
            {
                c = b;
            }
            else if (a < b)
            {
                c = a;
            }
            return c;
        }
       
         static void Main(string[] args)
        {
            int a = Convert.ToInt32(Console.ReadLine());
            int b = Convert.ToInt32(Console.ReadLine());
            int k =new Program().minnum(a, b);
            Console.WriteLine(k);
             Console.ReadKey();
        }       
        

谢谢。

此外，当a=b时,c是0。
你应该写：

static int minnum(int a, int b)
{
    int c = 0;
    if (a >= b)
    {
        c = b;
    }
    else if (a < b)
    {
        c = a;
    }
    return c;
}

或者：

static int minnum(int a, int b)
{
    return a <= b ? a : b;
}