Is it possible to read unknown number of lines from console in C#?

Question

有一个函数可以从控制台输入中读取一行（ Console.ReadLine() ），但是我希望读取一行或任意数量的行，这在编译时是未知的。

Answer 1

Of course it is. Just use just read a single line (using ReadLine() or whatever else you please) at a time within either a for loop (if you know at the beginning of reading how many lines you need) or within a while loop (if you want to stop reading when you reach EOF or a certain input).

EDIT:

Sure:

while ((line = Console.ReadLine()) != null) {
    // Do whatever you want here with line
}

Answer 2

Some of the other answers here loop until a null line is encountered while others expect the user to type something special like "EXIT". Keep in mind that reading from the console could be either a person typing or a redirected input file:

myprog.exe < somefile.txt

In the case of redirected input Console.ReadLine() would return null when it hits the end of the file. In the case of a user running the program interactively they'd have to know to how to enter the end of file character (Ctrl+Z followed by enter or F6 followed by enter). If it is an interactive user you might need to let them know how to signal the end of input.

Answer 3

The best thing to do here is use a loop:

string input;

Console.WriteLine("Input your text (type EXIT to terminate): ");
input = Console.ReadLine();

while (input.ToUpper() != "EXIT")
{
    // do something with input

    Console.WriteLine("Input your text(type EXIT to terminate): ");
    input = Console.ReadLine();
}

Or you could do something like this:

string input;

do
{
    Console.WriteLine("Input your text (type EXIT to terminate): ");
    input = Console.ReadLine();

    if (input.ToUpper() != "EXIT")
    {
        // do something with the input
    }
} while (input.ToUpper() != "EXIT");

Answer 4

simple example:

class Program
{
static void Main()
{
CountLinesInFile("test.txt"); // sample input in file format
}

static long CountLinesInFile(string f)
{
long count = 0;
using (StreamReader r = new StreamReader(f))
{
    string line;
    while ((line = r.ReadLine()) != null)
    {
    count++;
    }
}
return count;
}
}