Simple Calculator, System.FormatException
I'm trying to make a simple calculator and its fully working but when I calculate without a = button, my program completely crashes and gives the error:
System.FormatException: 'Input string was not in correct format.'
This is the code that it throws an error to:
second = double.Parse(aNumber);
// the strings and doubles:
String aNumber = "";
double first = 0.0;
c# calculator
edited Nov 20 at 20:04
D Manokhin
588219
asked Nov 20 at 17:57
Pride UK
1
|
show 1 more comment
I'm trying to make a simple calculator and its fully working but when I calculate without a = button, my program completely crashes and gives the error:
System.FormatException: 'Input string was not in correct format.'
This is the code that it throws an error to:
second = double.Parse(aNumber);
// the strings and doubles:
String aNumber = "";
double first = 0.0;
c# calculator
edited Nov 20 at 20:04
D Manokhin
588219
asked Nov 20 at 17:57
Pride UK
1
Show us more code. What issecond? How are you getting the user's value.
– Frontear
Nov 20 at 18:00
Yes, "" causes an exception. You can a) test for "" beforehand, or b) catch the exception.
– Mr Lister
Nov 20 at 18:04
double second = 0.0;
– Pride UK
Nov 20 at 18:14
3
You need to learn how to debug. Then learnDouble.TryParse.
– Dour High Arch
Nov 20 at 18:16
1
Possible duplicate of Input string was not in a correct format
– D Manokhin
Nov 20 at 18:20
|
show 1 more comment
I'm trying to make a simple calculator and its fully working but when I calculate without a = button, my program completely crashes and gives the error:
System.FormatException: 'Input string was not in correct format.'
This is the code that it throws an error to:
second = double.Parse(aNumber);
// the strings and doubles:
String aNumber = "";
double first = 0.0;
c# calculator
edited Nov 20 at 20:04
D Manokhin
588219
asked Nov 20 at 17:57
Pride UK
1
I'm trying to make a simple calculator and its fully working but when I calculate without a = button, my program completely crashes and gives the error:
System.FormatException: 'Input string was not in correct format.'
This is the code that it throws an error to:
second = double.Parse(aNumber);
// the strings and doubles:
String aNumber = "";
double first = 0.0;
c# calculator
c# calculator
edited Nov 20 at 20:04
D Manokhin
588219
asked Nov 20 at 17:57
Pride UK
1
edited Nov 20 at 20:04
D Manokhin
588219
asked Nov 20 at 17:57
Pride UK
1
edited Nov 20 at 20:04
D Manokhin
588219
edited Nov 20 at 20:04
D Manokhin
588219
edited Nov 20 at 20:04
D Manokhin
588219
588219
asked Nov 20 at 17:57
Pride UK
1
asked Nov 20 at 17:57
Pride UK
1
asked Nov 20 at 17:57
Pride UK
1
1
Show us more code. What issecond? How are you getting the user's value.
– Frontear
Nov 20 at 18:00
Yes, "" causes an exception. You can a) test for "" beforehand, or b) catch the exception.
– Mr Lister
Nov 20 at 18:04
double second = 0.0;
– Pride UK
Nov 20 at 18:14
3
You need to learn how to debug. Then learnDouble.TryParse.
– Dour High Arch
Nov 20 at 18:16
1
Possible duplicate of Input string was not in a correct format
– D Manokhin
Nov 20 at 18:20
|
show 1 more comment
Show us more code. What issecond? How are you getting the user's value.
– Frontear
Nov 20 at 18:00
Yes, "" causes an exception. You can a) test for "" beforehand, or b) catch the exception.
– Mr Lister
Nov 20 at 18:04
double second = 0.0;
– Pride UK
Nov 20 at 18:14
3
You need to learn how to debug. Then learnDouble.TryParse.
– Dour High Arch
Nov 20 at 18:16
1
Possible duplicate of Input string was not in a correct format
– D Manokhin
Nov 20 at 18:20
Show us more code. What is
second? How are you getting the user's value.– Frontear
Nov 20 at 18:00
Show us more code. What is
second? How are you getting the user's value.– Frontear
Nov 20 at 18:00
Yes, "" causes an exception. You can a) test for "" beforehand, or b) catch the exception.
– Mr Lister
Nov 20 at 18:04
Yes, "" causes an exception. You can a) test for "" beforehand, or b) catch the exception.
– Mr Lister
Nov 20 at 18:04
double second = 0.0;
– Pride UK
Nov 20 at 18:14
double second = 0.0;
– Pride UK
Nov 20 at 18:14
3
3
You need to learn how to debug. Then learn
Double.TryParse.– Dour High Arch
Nov 20 at 18:16
You need to learn how to debug. Then learn
Double.TryParse.– Dour High Arch
Nov 20 at 18:16
1
1
Possible duplicate of Input string was not in a correct format
– D Manokhin
Nov 20 at 18:20
Possible duplicate of Input string was not in a correct format
– D Manokhin
Nov 20 at 18:20
|
show 1 more comment
2 Answers
2
active
oldest
votes
b will be true or false if the try parse worked
d will contain the double or 0 if it fails
change anum to a valid number to test.
String anum = "";
double d = 0.0;
bool b = double.TryParse(anum, out d);
answered Nov 20 at 18:16
dcarl661
276
add a comment |
double.Parse will throw an exception if the input is not valid. So you either need to use try catch - or the preferred way would be to use double.TryParse as below. The value of y below will be set to the value if TryParse returns true.
class Program
{
static void Main(string args)
{
// This will cause an exception
var someString = "SomeValue";
var x = double.Parse(someString); // Comment this line out to run this example
// This will work
double y;
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
someString = "14.7";
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
}
}
answered Nov 20 at 18:21
Jon Vote
3708
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
b will be true or false if the try parse worked
d will contain the double or 0 if it fails
change anum to a valid number to test.
String anum = "";
double d = 0.0;
bool b = double.TryParse(anum, out d);
answered Nov 20 at 18:16
dcarl661
276
add a comment |
b will be true or false if the try parse worked
d will contain the double or 0 if it fails
change anum to a valid number to test.
String anum = "";
double d = 0.0;
bool b = double.TryParse(anum, out d);
answered Nov 20 at 18:16
dcarl661
276
add a comment |
b will be true or false if the try parse worked
d will contain the double or 0 if it fails
change anum to a valid number to test.
String anum = "";
double d = 0.0;
bool b = double.TryParse(anum, out d);
answered Nov 20 at 18:16
dcarl661
276
b will be true or false if the try parse worked
d will contain the double or 0 if it fails
change anum to a valid number to test.
String anum = "";
double d = 0.0;
bool b = double.TryParse(anum, out d);
answered Nov 20 at 18:16
dcarl661
276
answered Nov 20 at 18:16
dcarl661
276
answered Nov 20 at 18:16
dcarl661
276
answered Nov 20 at 18:16
dcarl661
276
276
add a comment |
add a comment |
double.Parse will throw an exception if the input is not valid. So you either need to use try catch - or the preferred way would be to use double.TryParse as below. The value of y below will be set to the value if TryParse returns true.
class Program
{
static void Main(string args)
{
// This will cause an exception
var someString = "SomeValue";
var x = double.Parse(someString); // Comment this line out to run this example
// This will work
double y;
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
someString = "14.7";
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
}
}
answered Nov 20 at 18:21
Jon Vote
3708
add a comment |
double.Parse will throw an exception if the input is not valid. So you either need to use try catch - or the preferred way would be to use double.TryParse as below. The value of y below will be set to the value if TryParse returns true.
class Program
{
static void Main(string args)
{
// This will cause an exception
var someString = "SomeValue";
var x = double.Parse(someString); // Comment this line out to run this example
// This will work
double y;
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
someString = "14.7";
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
}
}
answered Nov 20 at 18:21
Jon Vote
3708
add a comment |
double.Parse will throw an exception if the input is not valid. So you either need to use try catch - or the preferred way would be to use double.TryParse as below. The value of y below will be set to the value if TryParse returns true.
class Program
{
static void Main(string args)
{
// This will cause an exception
var someString = "SomeValue";
var x = double.Parse(someString); // Comment this line out to run this example
// This will work
double y;
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
someString = "14.7";
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
}
}
answered Nov 20 at 18:21
Jon Vote
3708
double.Parse will throw an exception if the input is not valid. So you either need to use try catch - or the preferred way would be to use double.TryParse as below. The value of y below will be set to the value if TryParse returns true.
class Program
{
static void Main(string args)
{
// This will cause an exception
var someString = "SomeValue";
var x = double.Parse(someString); // Comment this line out to run this example
// This will work
double y;
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
someString = "14.7";
if (double.TryParse(someString, out y))
{
Console.WriteLine(someString + " is a valid decimal");
}
else
{
Console.WriteLine(someString + " is not a valid decimal");
}
}
}
answered Nov 20 at 18:21
Jon Vote
3708
answered Nov 20 at 18:21
Jon Vote
3708
answered Nov 20 at 18:21
Jon Vote
3708
answered Nov 20 at 18:21
Jon Vote
3708
3708
add a comment |
add a comment |
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Show us more code. What is
second? How are you getting the user's value.– Frontear
Nov 20 at 18:00
Yes, "" causes an exception. You can a) test for "" beforehand, or b) catch the exception.
– Mr Lister
Nov 20 at 18:04
double second = 0.0;
– Pride UK
Nov 20 at 18:14
3
You need to learn how to debug. Then learn
Double.TryParse.– Dour High Arch
Nov 20 at 18:16
1
Possible duplicate of Input string was not in a correct format
– D Manokhin
Nov 20 at 18:20