问题
could anyone help me restart my program from line 46 if the user enters 1 (just after the comment where it states that the next code is going to ask the user for 2 inputs) and if the user enters -1 end it. I cannot think how to do it. I'm new to C# any help you could give would be great!
class Program
{
static void Main(string[] args)
{
//Displays data in correct Format
List<float> inputList = new List<float>();
TextReader tr = new StreamReader("c:/users/tom/documents/visual studio 2010/Projects/DistanceCalculator3/DistanceCalculator3/TextFile1.txt");
String input = Convert.ToString(tr.ReadToEnd());
String[] items = input.Split(',');
Console.WriteLine("Point Latitude Longtitude Elevation");
for (int i = 0; i < items.Length; i++)
{
if (i % 3 == 0)
{
Console.Write((i / 3) + "\t\t");
}
Console.Write(items[i]);
Console.Write("\t\t");
if (((i - 2) % 3) == 0)
{
Console.WriteLine();
}
}
Console.WriteLine();
Console.WriteLine();
// Ask for two inputs from the user which is then converted into 6 floats and transfered in class Coordinates
Console.WriteLine("Please enter the two points that you wish to know the distance between:");
string point = Console.ReadLine();
string[] pointInput = point.Split(' ');
int pointNumber = Convert.ToInt16(pointInput[0]);
int pointNumber2 = Convert.ToInt16(pointInput[1]);
Coordinates distance = new Coordinates();
distance.latitude = (Convert.ToDouble(items[pointNumber * 3]));
distance.longtitude = (Convert.ToDouble(items[(pointNumber * 3) + 1]));
distance.elevation = (Convert.ToDouble(items[(pointNumber * 3) + 2]));
distance.latitude2 = (Convert.ToDouble(items[pointNumber2 * 3]));
distance.longtitude2 = (Convert.ToDouble(items[(pointNumber2 * 3) + 1]));
distance.elevation2 = (Convert.ToDouble(items[(pointNumber2 * 3) + 2]));
//Calculate the distance between two points
const double PIx = 3.141592653589793;
const double RADIO = 6371;
double dlat = ((distance.latitude2) * (PIx / 180)) - ((distance.latitude) * (PIx / 180));
double dlon = ((distance.longtitude2) * (PIx / 180)) - ((distance.longtitude) * (PIx / 180));
double a = (Math.Sin(dlat / 2) * Math.Sin(dlat / 2)) + Math.Cos((distance.latitude) * (PIx / 180)) * Math.Cos((distance.latitude2) * (PIx / 180)) * (Math.Sin(dlon / 2) * Math.Sin(dlon / 2));
double angle = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
double ultimateDistance = (angle * RADIO);
Console.WriteLine("The distance between your two points is...");
Console.WriteLine(ultimateDistance);
//Repeat the program if the user enters 1, end the program if the user enters -1
Console.WriteLine("If you wish to calculate another distance type 1 and return, if you wish to end the program, type -1.");
Console.ReadLine();
if (Convert.ToInt16(Console.ReadLine()) == 1);
{
//here is where I need it to repeat
}
回答1:
bool exit = false;
do
{
Console.WriteLine("Please enter the two points that you wish to know the distance between:");
...
Console.WriteLine("If you wish to calculate another distance type 1 and return, if you wish to end the program, type -1.");
string input;
do
{
input = Console.ReadLine().Trim();
}
while (input != "1" && input != "-1");
if (input == -1) exit = true;
}
while (!exit);
But you would do much better to think about pushing logic into methods and functions such that you program is built up of much smaller building blocks.
You should be aiming towards something like this:
bool exit = false;
do
{
Point[] points = ReadCoordinates();
Whatever result = CalculateWhatever();
DisplayResults(results);
exit = ShouldExit();
}
while (!exit);
This makes the outer loop of your program self documenting and the methods self explanatory.
回答2:
if (Convert.ToInt16(Console.ReadLine()) == 1);
{
Main(args)
}
回答3:
That's quite an odd thing to do. Have you looked into the while loop?
You could make a method of the above structure and loop it, while userinput equals 1 if it equals -1, call the following statement
Application.Exit()
回答4:
Can use Goto to make the program loop on user input.
public static void Main(string[] args)
{
RestartApplication:
//// Displays data in correct Format
TextReader textReader = new StreamReader("c:/users/tom/documents/visual studio 2010/Projects/DistanceCalculator3/DistanceCalculator3/TextFile1.txt");
var input = Convert.ToString(textReader.ReadToEnd());
var items = input.Split(',');
Console.WriteLine("Point Latitude Longtitude Elevation");
for (var i = 0; i < items.Length; i++)
{
if (i % 3 == 0)
{
Console.Write((i / 3) + "\t\t");
}
Console.Write(items[i]);
Console.Write("\t\t");
if (((i - 2) % 3) == 0)
{
Console.WriteLine();
}
}
Console.WriteLine();
Console.WriteLine();
//// Ask for two inputs from the user which is then converted into 6 floats and transferred in class Coordinates
Console.WriteLine("Please enter the two points that you wish to know the distance between:");
var point = Console.ReadLine();
string[] pointInput;
if (point != null)
{
pointInput = point.Split(' ');
}
else
{
goto RestartApplication;
}
var pointNumber = Convert.ToInt16(pointInput[0]);
var pointNumber2 = Convert.ToInt16(pointInput[1]);
var distance = new Coordinates
{
Latitude = Convert.ToDouble(items[pointNumber * 3]),
Longtitude = Convert.ToDouble(items[(pointNumber * 3) + 1]),
Elevation = Convert.ToDouble(items[(pointNumber * 3) + 2]),
Latitude2 = Convert.ToDouble(items[pointNumber2 * 3]),
Longtitude2 = Convert.ToDouble(items[(pointNumber2 * 3) + 1]),
Elevation2 = Convert.ToDouble(items[(pointNumber2 * 3) + 2])
};
//// Calculate the distance between two points
const double PIx = 3.141592653589793;
const double Radio = 6371;
var dlat = (distance.Latitude2 * (PIx / 180)) - (distance.Latitude * (PIx / 180));
var dlon = (distance.Longtitude2 * (PIx / 180)) - (distance.Longtitude * (PIx / 180));
var a = (Math.Sin(dlat / 2) * Math.Sin(dlat / 2)) + Math.Cos(distance.Latitude * (PIx / 180)) * Math.Cos(distance.Latitude2 * (PIx / 180)) * (Math.Sin(dlon / 2) * Math.Sin(dlon / 2));
var angle = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
var ultimateDistance = angle * Radio;
Console.WriteLine("The distance between your two points is...");
Console.WriteLine(ultimateDistance);
//// Repeat the program if the user enters 1, end the program if the user enters -1
Console.WriteLine("If you wish to calculate another distance type 1 and return, if you wish to end the program, type -1.");
var userInput = Console.ReadLine();
if (Convert.ToInt16(userInput) == 1)
{
//// Here is where the application will repeat.
goto RestartApplication;
}
}
also did a bit of code formatting. Hope it helps.
回答5:
You could do that with goto, be aware however that this is considered bad practice.
static void Main(string[] args)
{
...
MyLabel:
...
if (Convert.ToInt16(Console.ReadLine()) == 1);
{
//here is where I need it to repeat
goto MyLabel;
}
来源：https://stackoverflow.com/questions/13066736/restart-program-from-a-certain-line-with-an-if-statement