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Start your free trialtung nguyen
Courses Plus Student 1,666 PointsFormatException
i have this err. and i dont know how to fix it. pls help me System.ArgumentNullException: Value cannot be null. Parameter name: String at System.Number.StringToNumber (System.String str, System.Globalization.NumberStyles options, System.Number+NumberBuffer& number, System.Globalization.NumberFormatInfo info, System.Boolean parseDecimal) [0x00054] in /builddir/build/BUILD/mono-4.8.1/mcs/class/referencesource/mscorlib/system/number.cs:1074 at System.Number.ParseInt32 (System.String s, System.Globalization.NumberStyles style, System.Globalization.NumberFormatInfo info) [0x00014] in /builddir/build/BUILD/mono-4.8.1/mcs/class/referencesource/mscorlib/system/number.cs:745 at System.Int32.Parse (System.String s) [0x00000] in /builddir/build/BUILD/mono-4.8.1/mcs/class/referencesource/mscorlib/system/int32.cs:120 at Treehouse.CodeChallenges.Program.Main () [0x00011] in <63c0b697f8714d7dadfbc9d3af622980>:0 at MonoTester.Run () [0x00208] in /workdir/MonoTester.cs:140
using System;
namespace Treehouse.CodeChallenges
{
class Program
{
static void Main()
{
int i = 0;
while(true)
try {
Console.Write("Enter the number of times to print \"Yay!\": ");
int number = int.Parse(Console.ReadLine());
while (i < number)
{ Console.WriteLine("\"Yay!\""); i++; }
break;
}
catch(FormatException) { Console.WriteLine("You must enter a whole number.");continue; }
}
}
}
2 Answers
Richard Schwind
1,785 PointsTry using:
int number = Convert.ToInt32(Console.ReadLine());
Instead of:
int number = int.Parse(Console.ReadLine());
int.Parse() throws an ArgumentNullException when it is passed a null argument. However, Convert.ToInt32() returns 0 when it is passed a null argument. For a more in-depth explanation on how these two methods work, check out this discussion on StackOverflow.
tung nguyen
Courses Plus Student 1,666 Pointsoh i see, thank you so much ^^