Compare your code with this. You have not added the () properly in your if else block.
Following code is working fine.
class compare
{
int num1, num2, num3;
public void accept()
{
Console.WriteLine("Enter First Number");
num1 = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Enter Second Number");
num2 = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Enter Third Number");
num3 = Convert.ToInt32(Console.ReadLine());
}
public void display()
{
if((num1>num2)&&(num1>num3))
{
Console.WriteLine("This No is greatest {0}",num1);
}
else if((num2>num1)&&(num2>num3))
{
Console.WriteLine("This No is greatest {0}",num2);
}
else
{
Console.WriteLine("This No is greatest {0}",num3);
}
}
static void Main(string[] args)
{
compare cmp = new compare();
cmp.accept();
cmp.display();
Console.Read();
}
}