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Adham Ali
Courses Plus Student 1,112 PointsI dont know what is wrong with my code. It throws a NullArgumentException
I did as it told me... if the user entered a invalid input it catches It and recall the method instead of including the whole method body in a loop and writing continue to jump to the top of the code
using System;
namespace Treehouse.CodeChallenges
{
class Program
{
static void Main()
{
Console.Write("Enter the number of times to print \"Yay!\": ");
string userInput = Console.ReadLine();
var numbers = 0;
try
{
numbers = int.Parse(userInput);
}
catch(FormatException)
{
Console.WriteLine("You must enter a whole number.");
Main();
}
int counter=0;
while(numbers != counter)
{
Console.WriteLine("Yay!");
counter++;
}
}
}
}
4 Answers
Patrik Horváth
11,110 PointsTASK 1 : you need FOR LOOP
using System;
namespace Treehouse.CodeChallenges
{
class Program
{
static void Main()
{
Console.Write("Enter the number of times to print \"Yay!\": ");
string userInput = Console.ReadLine();
for (int i=0; i < int.Parse(userInput); i++)
{
Console.Write("Yay!");
}
}
}
}
TASK 2:
using System;
namespace Treehouse.CodeChallenges
{
class Program
{
static void Main()
{
Console.Write("Enter the number of times to print \"Yay!\": ");
string userInput = Console.ReadLine();
try {
for (int i=0; i < int.Parse(userInput); i++)
{
Console.Write("Yay!");
}
} catch (Exception e) {
Console.Write("You must enter a whole number.");
}
}
}
}
TASK 3 :
using System;
namespace Treehouse.CodeChallenges
{
class Program
{
static void Main()
{
Console.Write("Enter the number of times to print \"Yay!\": ");
string userInput = Console.ReadLine();
try {
if (int.Parse(userInput) < 0) {
Console.Write("You must enter a positive number");
} else {
for (int i=0; i < int.Parse(userInput); i++)
{
Console.Write("Yay!");
}
}
}catch (Exception e) {
Console.Write("You must enter a whole number.");
}
}
}
}
Adham Ali
Courses Plus Student 1,112 Pointsyeah but whats wrong with my code?
Patrik Horváth
11,110 Pointsfirst part was good but why number = 0 ? you can simple
int number = numbers = int.Parse(userInput);
then inside TRY you have to loop Console.Write based on user INPUT ( number )
and you CANT call main() because its not allowed in any programing language call MAIN method / function, because main can be called only ONCE when probgram RUNs
Patrik Horváth
11,110 Pointsif you want LOOP something more times you have to use FOR / WHILE / DO WHILE / FOR EACH
if not your program will not repeat
try on your own write numbers from 0 to 100 :)
Adham Ali
Courses Plus Student 1,112 PointsFirst of all: I always call Main Method (BUT INSIDE THE BODY OF ITS OWN).
Because simply its just a method. Yeah the compiler runs it in the beginning, Its the entry point.
Maybe it uses reflection or something I wish I knew.
But it is just a method. How it could prevent us from calling it
Patrik Horváth
11,110 Pointsyea you can call main() because its only 1 way how to run program :)
Adham Ali
Courses Plus Student 1,112 PointsI run it maunaly in the code I write for instance for jumping the the beginning of the method if some input was invalid and I print a text to make the user enter an input again