How to re-ask for input in try catch statement
string l = Console.ReadLine();
try
{
int.Parse(l);
}
catch (FormatException)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
}
As you can see, I have asked for input, but if the user enters a non-integral answer such as the letter "f", the catch statement catches it, but then throws the exception again afterwards, because the variable "l" still equals "f". Help?
c#
edited May 15 '13 at 20:42
Sean Bright
93.6k14114128
asked May 15 '13 at 20:39
omniomni
4421516
add a comment |
string l = Console.ReadLine();
try
{
int.Parse(l);
}
catch (FormatException)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
}
As you can see, I have asked for input, but if the user enters a non-integral answer such as the letter "f", the catch statement catches it, but then throws the exception again afterwards, because the variable "l" still equals "f". Help?
c#
edited May 15 '13 at 20:42
Sean Bright
93.6k14114128
asked May 15 '13 at 20:39
omniomni
4421516
5
Seems you should learn what a loop is before you start using try catch.
– ChaosPandion
May 15 '13 at 20:42
add a comment |
string l = Console.ReadLine();
try
{
int.Parse(l);
}
catch (FormatException)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
}
As you can see, I have asked for input, but if the user enters a non-integral answer such as the letter "f", the catch statement catches it, but then throws the exception again afterwards, because the variable "l" still equals "f". Help?
c#
edited May 15 '13 at 20:42
Sean Bright
93.6k14114128
asked May 15 '13 at 20:39
omniomni
4421516
string l = Console.ReadLine();
try
{
int.Parse(l);
}
catch (FormatException)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
}
As you can see, I have asked for input, but if the user enters a non-integral answer such as the letter "f", the catch statement catches it, but then throws the exception again afterwards, because the variable "l" still equals "f". Help?
c#
c#
edited May 15 '13 at 20:42
Sean Bright
93.6k14114128
asked May 15 '13 at 20:39
omniomni
4421516
edited May 15 '13 at 20:42
Sean Bright
93.6k14114128
asked May 15 '13 at 20:39
omniomni
4421516
edited May 15 '13 at 20:42
Sean Bright
93.6k14114128
edited May 15 '13 at 20:42
Sean Bright
93.6k14114128
edited May 15 '13 at 20:42
Sean Bright
93.6k14114128
93.6k14114128
asked May 15 '13 at 20:39
omniomni
4421516
asked May 15 '13 at 20:39
omniomni
4421516
asked May 15 '13 at 20:39
omniomni
4421516
4421516
5
Seems you should learn what a loop is before you start using try catch.
– ChaosPandion
May 15 '13 at 20:42
add a comment |
5
Seems you should learn what a loop is before you start using try catch.
– ChaosPandion
May 15 '13 at 20:42
5
5
Seems you should learn what a loop is before you start using try catch.
– ChaosPandion
May 15 '13 at 20:42
Seems you should learn what a loop is before you start using try catch.
– ChaosPandion
May 15 '13 at 20:42
add a comment |
4 Answers
4
active
oldest
votes
You can use int.TryParse instead of catching exceptions. It returns whether the parse was successful, so you can check it in a loop until the input is valid e.g.
int i;
bool valid = false;
do {
Console.WriteLine("Enter an int: ");
string input = Console.ReadLine();
valid = int.TryParse(input, out i);
} while(! valid);
//use i
answered May 15 '13 at 20:42
LeeLee
120k14177248
There's no need to declare an additionalboolfield for this if you embed theTryCatchin the condition of the loop.
– qJake
May 15 '13 at 20:46
add a comment |
You'll want to use TryParse with a while loop (since your condition can fail an infinite number of times).
string l = Console.ReadLine();
int line = 0;
while(!int.TryParse(l, out line))
{
Console.WriteLine("Try again.");
l = Console.ReadLine();
}
// line contains a valid number here.
answered May 15 '13 at 20:43
qJakeqJake
12.1k1064114
add a comment |
don't do it that way. Use TryParse instead
string l = Console.ReadLine();
int i;
while(int.TryParse(l, out i) == false)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
l = Console.ReadLine();
}
answered May 15 '13 at 20:41
Sam I amSam I am
27k115995
== false? Why not!?
– qJake
May 15 '13 at 20:43
@SpikeX - Its so you know it is a boolean!!!!
– ChaosPandion
May 15 '13 at 20:44
@SpikeX I personally think that!int.TryParse(l, out i)looks too similar toint.TryParse(l, out i)It improves readability for me
– Sam I am
May 15 '13 at 20:44
@ChaosPandion Your IDE should be responsible for relaying type information, not your code.
– qJake
May 15 '13 at 20:44
@SpikeX - I was being snarky.
– ChaosPandion
May 15 '13 at 20:46
|
show 1 more comment
There are various ways you can handle this. One way it to wrap all of this in a loop allowing a given number of retries or just a while loop that keeps going until the user enters valid input. Another is to put it all in a method and call it recursively from the catch block. I think the best solution is neither, instead I would use Int.TryParse and I would have that inside a while loop like;
while (!Int32.TryParse(input, out line))
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
input = Console.ReadLine();
}
edited Nov 21 '18 at 12:33
Dmitry Bychenko
111k1098140
answered May 15 '13 at 20:43
evanmcdonnalevanmcdonnal
28.7k115681
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
You can use int.TryParse instead of catching exceptions. It returns whether the parse was successful, so you can check it in a loop until the input is valid e.g.
int i;
bool valid = false;
do {
Console.WriteLine("Enter an int: ");
string input = Console.ReadLine();
valid = int.TryParse(input, out i);
} while(! valid);
//use i
answered May 15 '13 at 20:42
LeeLee
120k14177248
There's no need to declare an additionalboolfield for this if you embed theTryCatchin the condition of the loop.
– qJake
May 15 '13 at 20:46
add a comment |
You can use int.TryParse instead of catching exceptions. It returns whether the parse was successful, so you can check it in a loop until the input is valid e.g.
int i;
bool valid = false;
do {
Console.WriteLine("Enter an int: ");
string input = Console.ReadLine();
valid = int.TryParse(input, out i);
} while(! valid);
//use i
answered May 15 '13 at 20:42
LeeLee
120k14177248
There's no need to declare an additionalboolfield for this if you embed theTryCatchin the condition of the loop.
– qJake
May 15 '13 at 20:46
add a comment |
You can use int.TryParse instead of catching exceptions. It returns whether the parse was successful, so you can check it in a loop until the input is valid e.g.
int i;
bool valid = false;
do {
Console.WriteLine("Enter an int: ");
string input = Console.ReadLine();
valid = int.TryParse(input, out i);
} while(! valid);
//use i
answered May 15 '13 at 20:42
LeeLee
120k14177248
You can use int.TryParse instead of catching exceptions. It returns whether the parse was successful, so you can check it in a loop until the input is valid e.g.
int i;
bool valid = false;
do {
Console.WriteLine("Enter an int: ");
string input = Console.ReadLine();
valid = int.TryParse(input, out i);
} while(! valid);
//use i
answered May 15 '13 at 20:42
LeeLee
120k14177248
answered May 15 '13 at 20:42
LeeLee
120k14177248
answered May 15 '13 at 20:42
LeeLee
120k14177248
answered May 15 '13 at 20:42
LeeLee
120k14177248
120k14177248
There's no need to declare an additionalboolfield for this if you embed theTryCatchin the condition of the loop.
– qJake
May 15 '13 at 20:46
add a comment |
There's no need to declare an additionalboolfield for this if you embed theTryCatchin the condition of the loop.
– qJake
May 15 '13 at 20:46
There's no need to declare an additional
bool field for this if you embed the TryCatch in the condition of the loop.– qJake
May 15 '13 at 20:46
There's no need to declare an additional
bool field for this if you embed the TryCatch in the condition of the loop.– qJake
May 15 '13 at 20:46
add a comment |
You'll want to use TryParse with a while loop (since your condition can fail an infinite number of times).
string l = Console.ReadLine();
int line = 0;
while(!int.TryParse(l, out line))
{
Console.WriteLine("Try again.");
l = Console.ReadLine();
}
// line contains a valid number here.
answered May 15 '13 at 20:43
qJakeqJake
12.1k1064114
add a comment |
You'll want to use TryParse with a while loop (since your condition can fail an infinite number of times).
string l = Console.ReadLine();
int line = 0;
while(!int.TryParse(l, out line))
{
Console.WriteLine("Try again.");
l = Console.ReadLine();
}
// line contains a valid number here.
answered May 15 '13 at 20:43
qJakeqJake
12.1k1064114
add a comment |
You'll want to use TryParse with a while loop (since your condition can fail an infinite number of times).
string l = Console.ReadLine();
int line = 0;
while(!int.TryParse(l, out line))
{
Console.WriteLine("Try again.");
l = Console.ReadLine();
}
// line contains a valid number here.
answered May 15 '13 at 20:43
qJakeqJake
12.1k1064114
You'll want to use TryParse with a while loop (since your condition can fail an infinite number of times).
string l = Console.ReadLine();
int line = 0;
while(!int.TryParse(l, out line))
{
Console.WriteLine("Try again.");
l = Console.ReadLine();
}
// line contains a valid number here.
answered May 15 '13 at 20:43
qJakeqJake
12.1k1064114
edited May 15 '13 at 20:48
answered May 15 '13 at 20:43
qJakeqJake
12.1k1064114
answered May 15 '13 at 20:43
qJakeqJake
12.1k1064114
answered May 15 '13 at 20:43
qJakeqJake
12.1k1064114
12.1k1064114
add a comment |
add a comment |
don't do it that way. Use TryParse instead
string l = Console.ReadLine();
int i;
while(int.TryParse(l, out i) == false)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
l = Console.ReadLine();
}
answered May 15 '13 at 20:41
Sam I amSam I am
27k115995
== false? Why not!?
– qJake
May 15 '13 at 20:43
@SpikeX - Its so you know it is a boolean!!!!
– ChaosPandion
May 15 '13 at 20:44
@SpikeX I personally think that!int.TryParse(l, out i)looks too similar toint.TryParse(l, out i)It improves readability for me
– Sam I am
May 15 '13 at 20:44
@ChaosPandion Your IDE should be responsible for relaying type information, not your code.
– qJake
May 15 '13 at 20:44
@SpikeX - I was being snarky.
– ChaosPandion
May 15 '13 at 20:46
|
show 1 more comment
don't do it that way. Use TryParse instead
string l = Console.ReadLine();
int i;
while(int.TryParse(l, out i) == false)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
l = Console.ReadLine();
}
answered May 15 '13 at 20:41
Sam I amSam I am
27k115995
== false? Why not!?
– qJake
May 15 '13 at 20:43
@SpikeX - Its so you know it is a boolean!!!!
– ChaosPandion
May 15 '13 at 20:44
@SpikeX I personally think that!int.TryParse(l, out i)looks too similar toint.TryParse(l, out i)It improves readability for me
– Sam I am
May 15 '13 at 20:44
@ChaosPandion Your IDE should be responsible for relaying type information, not your code.
– qJake
May 15 '13 at 20:44
@SpikeX - I was being snarky.
– ChaosPandion
May 15 '13 at 20:46
|
show 1 more comment
don't do it that way. Use TryParse instead
string l = Console.ReadLine();
int i;
while(int.TryParse(l, out i) == false)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
l = Console.ReadLine();
}
answered May 15 '13 at 20:41
Sam I amSam I am
27k115995
don't do it that way. Use TryParse instead
string l = Console.ReadLine();
int i;
while(int.TryParse(l, out i) == false)
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
l = Console.ReadLine();
}
answered May 15 '13 at 20:41
Sam I amSam I am
27k115995
answered May 15 '13 at 20:41
Sam I amSam I am
27k115995
answered May 15 '13 at 20:41
Sam I amSam I am
27k115995
answered May 15 '13 at 20:41
Sam I amSam I am
27k115995
27k115995
== false? Why not!?
– qJake
May 15 '13 at 20:43
@SpikeX - Its so you know it is a boolean!!!!
– ChaosPandion
May 15 '13 at 20:44
@SpikeX I personally think that!int.TryParse(l, out i)looks too similar toint.TryParse(l, out i)It improves readability for me
– Sam I am
May 15 '13 at 20:44
@ChaosPandion Your IDE should be responsible for relaying type information, not your code.
– qJake
May 15 '13 at 20:44
@SpikeX - I was being snarky.
– ChaosPandion
May 15 '13 at 20:46
|
show 1 more comment
== false? Why not!?
– qJake
May 15 '13 at 20:43
@SpikeX - Its so you know it is a boolean!!!!
– ChaosPandion
May 15 '13 at 20:44
@SpikeX I personally think that!int.TryParse(l, out i)looks too similar toint.TryParse(l, out i)It improves readability for me
– Sam I am
May 15 '13 at 20:44
@ChaosPandion Your IDE should be responsible for relaying type information, not your code.
– qJake
May 15 '13 at 20:44
@SpikeX - I was being snarky.
– ChaosPandion
May 15 '13 at 20:46
== false? Why not !?– qJake
May 15 '13 at 20:43
== false? Why not !?– qJake
May 15 '13 at 20:43
@SpikeX - Its so you know it is a boolean!!!!
– ChaosPandion
May 15 '13 at 20:44
@SpikeX - Its so you know it is a boolean!!!!
– ChaosPandion
May 15 '13 at 20:44
@SpikeX I personally think that
!int.TryParse(l, out i) looks too similar to int.TryParse(l, out i) It improves readability for me– Sam I am
May 15 '13 at 20:44
@SpikeX I personally think that
!int.TryParse(l, out i) looks too similar to int.TryParse(l, out i) It improves readability for me– Sam I am
May 15 '13 at 20:44
@ChaosPandion Your IDE should be responsible for relaying type information, not your code.
– qJake
May 15 '13 at 20:44
@ChaosPandion Your IDE should be responsible for relaying type information, not your code.
– qJake
May 15 '13 at 20:44
@SpikeX - I was being snarky.
– ChaosPandion
May 15 '13 at 20:46
@SpikeX - I was being snarky.
– ChaosPandion
May 15 '13 at 20:46
|
show 1 more comment
There are various ways you can handle this. One way it to wrap all of this in a loop allowing a given number of retries or just a while loop that keeps going until the user enters valid input. Another is to put it all in a method and call it recursively from the catch block. I think the best solution is neither, instead I would use Int.TryParse and I would have that inside a while loop like;
while (!Int32.TryParse(input, out line))
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
input = Console.ReadLine();
}
edited Nov 21 '18 at 12:33
Dmitry Bychenko
111k1098140
answered May 15 '13 at 20:43
evanmcdonnalevanmcdonnal
28.7k115681
add a comment |
There are various ways you can handle this. One way it to wrap all of this in a loop allowing a given number of retries or just a while loop that keeps going until the user enters valid input. Another is to put it all in a method and call it recursively from the catch block. I think the best solution is neither, instead I would use Int.TryParse and I would have that inside a while loop like;
while (!Int32.TryParse(input, out line))
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
input = Console.ReadLine();
}
edited Nov 21 '18 at 12:33
Dmitry Bychenko
111k1098140
answered May 15 '13 at 20:43
evanmcdonnalevanmcdonnal
28.7k115681
add a comment |
There are various ways you can handle this. One way it to wrap all of this in a loop allowing a given number of retries or just a while loop that keeps going until the user enters valid input. Another is to put it all in a method and call it recursively from the catch block. I think the best solution is neither, instead I would use Int.TryParse and I would have that inside a while loop like;
while (!Int32.TryParse(input, out line))
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
input = Console.ReadLine();
}
edited Nov 21 '18 at 12:33
Dmitry Bychenko
111k1098140
answered May 15 '13 at 20:43
evanmcdonnalevanmcdonnal
28.7k115681
There are various ways you can handle this. One way it to wrap all of this in a loop allowing a given number of retries or just a while loop that keeps going until the user enters valid input. Another is to put it all in a method and call it recursively from the catch block. I think the best solution is neither, instead I would use Int.TryParse and I would have that inside a while loop like;
while (!Int32.TryParse(input, out line))
{
Console.WriteLine("Invalid input. Please enter 1, 2, or 3.");
input = Console.ReadLine();
}
edited Nov 21 '18 at 12:33
Dmitry Bychenko
111k1098140
answered May 15 '13 at 20:43
evanmcdonnalevanmcdonnal
28.7k115681
edited Nov 21 '18 at 12:33
Dmitry Bychenko
111k1098140
edited Nov 21 '18 at 12:33
Dmitry Bychenko
111k1098140
edited Nov 21 '18 at 12:33
Dmitry Bychenko
111k1098140
111k1098140
answered May 15 '13 at 20:43
evanmcdonnalevanmcdonnal
28.7k115681
answered May 15 '13 at 20:43
evanmcdonnalevanmcdonnal
28.7k115681
answered May 15 '13 at 20:43
evanmcdonnalevanmcdonnal
28.7k115681
28.7k115681
add a comment |
add a comment |
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5
Seems you should learn what a loop is before you start using try catch.
– ChaosPandion
May 15 '13 at 20:42