我试图创建一个 C# 程序，为用户提供 3 个选项：
创建名称（让用户输入他们的名字和姓氏并将其显示为 J.Blogg）
一个数字的阶乘（输出例如 5x4x3x2x1 =120，它是 5 的阶乘
退出
我的程序工作正常，但是当我尝试选择选项 1（创建名称）然后选择选项 2 时，它转到选项 1，然后它不允许我退出（选项 3）。我是编程新手，所以它可能很简单，但我看不出我哪里出错了，任何帮助都会非常有用。我想保持相同的布局，我认为我的问题可能是循环，但任何帮助和改进都会很棒。
static void Main(string[] args)
{
//The value returned from the topmenu method is stored in a variable called useroption
int useroption;
useroption = topmenu();
// excute while loop untill option is not 1-3
do
{
if (useroption == 1)
{
Console.Clear();
Createname();
//break;
}
if (useroption == 2)
{
Console.Clear();
factorial();
// break;
}
if (useroption == 3)
{
Console.Clear();
Console.WriteLine("Thank you for using my program, Good bye !!!");
// break;
}
//topmenu();
}
while (useroption != 3);
Console.ReadKey();
}
//This method present the user with an menu which the user has a choice of 3 options
static int topmenu()
{
int option;
string option_str;
Console.Clear();
Console.WriteLine("********************************************************************************");
Console.WriteLine("********************************************************************************");
Console.WriteLine("********* OPTION 1 : Enter your name *********");
Console.WriteLine("********* OPTION 2 : Enter the number you want to factorise *********");
Console.WriteLine("********* OPTION 3 : Quit *********");
Console.WriteLine("********************************************************************************");
Console.WriteLine("********************************************************************************");
option_str = Console.ReadLine();
option = Convert.ToInt32(option_str);
Console.Clear();
if (option < 0 || option > 3)
{
Console.WriteLine("You have enter an invald option,");
Console.WriteLine("Please chose a option between 1-3 (Please press any key to return to main menu)");
Console.ReadLine();
Console.Clear();
topmenu();
}
else
{
Console.WriteLine("You have chosen option: " + option + " (Please press any key continue)");
}
Console.ReadKey();
return option;
}
//this method asks user to enter their name (1st name then surname) and presents it back to the user as their intial(1st name) and surname
static void Createname()
{
string firstname, surname, firstname_str, surname_str, userfullname;
Console.Clear();
Console.WriteLine("Please enter your first name ");
firstname_str = Console.ReadLine();
firstname = Convert.ToString(firstname_str);
Console.Clear();
Console.WriteLine("Please enter your surname name ");
surname_str = Console.ReadLine();
surname = Convert.ToString(surname_str);
Console.Clear();
userfullname = firstname + surname;
Console.WriteLine("You have entered your name as " + firstname[0] + "." + surname);
Console.WriteLine("(Please press any key to return to main menu)");
Console.ReadKey();
topmenu();
}
//this method asks the user to enter a number and returns the factorial of that number
static double factorial()
{
string number_str;
double factorial = 1;
Console.WriteLine("Please enter number");
number_str = Console.ReadLine();
int num = Convert.ToInt32(number_str);
// If statement is used so when the user inputs 0, INVALID is outputed
if (num <= 0)
{
Console.WriteLine("You have enter an invald option");
Console.WriteLine("Please enter number");
number_str = Console.ReadLine();
Console.Clear();
num = Convert.ToInt32(number_str);
//Console.Clear();
//topmenu();
//number_str = Console.ReadLine();
}
if (num >= 0)
{
while (num != 0)
{
for (int i = num; i >= 1; i--)
{
factorial = factorial * i;
Console.Write(i + " * ");
}
Console.WriteLine("= "+factorial+ " which is factorial of " + number_str.ToString() );
Console.WriteLine("(please any key to return to main menu)");
Console.ReadKey();
Console.Clear();
topmenu();
}
}
return factorial;
}
}
}