Where is error?

Question

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SoloLearn
{
class Program
{
static void Main(string[] args)
{
int num = Convert.ToInt32(Console.ReadLine());

Int e = 1;
Int m = 2;
Int h = 3;
Switch (num) {
Case 1:
Console.WriteLine("Easy");
break;
Case 2:
Console.WriteLine("Medium");
break;
Case 3:
Console.WriteLine("Hard");
break;
default:
Console.WriteLine("Invalid Option");
break;
}
}
}
}

Answer 1

c# is case-sensitive and the case of int, switch, and "case" is wrong.

Here is a fixed version of your code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SoloLearn
{
class Program
{
static void Main(string[] args)
{
int num = Convert.ToInt32(Console.ReadLine());

int e = 1;
int m = 2;
int h = 3;
switch (num) {
case 1:
Console.WriteLine("Easy");
break;
case 2:
Console.WriteLine("Medium");
break;
case 3:
Console.WriteLine("Hard");
break;
default:
Console.WriteLine("Invalid Option");
break;
}
}
}
}