C error Use of unassigned local variable

Question

I m not sure why I m getting this error  but shouldn t this code compile  since I m already checking to see if queue is getting initialized    public static void Main String   args        Byte maxSize      Queue queue       if args Length    0                if Byte TryParse args 0   out maxSize               queue   new Queue   MaxSize   maxSize           else             Environment Exit 0             else               Environment Exit 0              for Byte j   0  j  lt  queue MaxSize  j            queue Insert j       for Byte j   0  j  lt  queue MaxSize  j            Console WriteLine queue Remove         So if queue is not initialized  then the for loops aren t reachable right  Since the program already terminates with Environment Exit 0    Hope ya ll can give me some pointers     Thanks

User · Answer

The compiler only knows that the code is or isn t reachable if you use  return   Think of Environment Exit   as a function that you call  and the compiler don t know that it will close the application

User · Answer

The compiler doesn t know that Environment Exit   does not return   Why not just  return  from Main

User · Answer

The compiler only knows that the code is or isn t reachable if you use  return   Think of Environment Exit   as a function that you call  and the compiler don t know that it will close the application

User · Answer

The compiler doesn t know that the Environment Exit   is going to terminate the program  it just sees you executing a static method on a class   Just initialize queue to null when you declare it   Queue queue   null

User · Answer

The compiler only knows that the code is or isn t reachable if you use  return   Think of Environment Exit   as a function that you call  and the compiler don t know that it will close the application

User · Answer

A couple of different ways to solve the problem   Just replace Environment Exit with return  The compiler knows that return ends the method  but doesn t know that Environment Exit does   static void Main string   args        if args Length    0           if Byte TryParse args 0   out maxSize            queue   new Queue   MaxSize   maxSize          else          return        else          return         Of course  you can really only get away with that because you re using 0 as your exit code in all cases  Really  you should return an int instead of using Environment Exit  For this particular case  this would be my preferred method   static int Main string   args        if args Length    0           if Byte TryParse args 0   out maxSize            queue   new Queue   MaxSize   maxSize          else          return 1        else          return 2            Initialize queue to null  which is really just a compiler trick that says  I ll figure out my own uninitialized variables  thank you very much   It s a useful trick  but I don t like it in this case - you have too many if branches to easily check that you re doing it properly  If you really wanted to do it this way  something like this would be clearer   static void Main string   args      Byte maxSize    Queue queue   null     if args Length    0     Byte TryParse args 0   out maxSize          Environment Exit 0         queue   new Queue   MaxSize   maxSize      for Byte j   0  j  lt  queue MaxSize  j        queue Insert j     for Byte j   0  j  lt  queue MaxSize  j        Console WriteLine queue Remove         Add a return statement after Environment Exit  Again  this is more of a compiler trick - but is slightly more legit IMO because it adds semantics for humans as well  though it ll keep you from that vaunted 100  code coverage   static void Main String   args      if args Length    0         if Byte TryParse args 0   out maxSize             queue   new Queue   MaxSize   maxSize          else           Environment Exit 0           return             else         Environment Exit 0        return         for Byte j   0  j  lt  queue MaxSize  j         queue Insert j     for Byte j   0  j  lt  queue MaxSize  j         Console WriteLine queue Remove

User · Answer

The compiler doesn t know that Environment Exit   does not return   Why not just  return  from Main

User · Answer

A couple of different ways to solve the problem   Just replace Environment Exit with return  The compiler knows that return ends the method  but doesn t know that Environment Exit does   static void Main string   args        if args Length    0           if Byte TryParse args 0   out maxSize            queue   new Queue   MaxSize   maxSize          else          return        else          return         Of course  you can really only get away with that because you re using 0 as your exit code in all cases  Really  you should return an int instead of using Environment Exit  For this particular case  this would be my preferred method   static int Main string   args        if args Length    0           if Byte TryParse args 0   out maxSize            queue   new Queue   MaxSize   maxSize          else          return 1        else          return 2            Initialize queue to null  which is really just a compiler trick that says  I ll figure out my own uninitialized variables  thank you very much   It s a useful trick  but I don t like it in this case - you have too many if branches to easily check that you re doing it properly  If you really wanted to do it this way  something like this would be clearer   static void Main string   args      Byte maxSize    Queue queue   null     if args Length    0     Byte TryParse args 0   out maxSize          Environment Exit 0         queue   new Queue   MaxSize   maxSize      for Byte j   0  j  lt  queue MaxSize  j        queue Insert j     for Byte j   0  j  lt  queue MaxSize  j        Console WriteLine queue Remove         Add a return statement after Environment Exit  Again  this is more of a compiler trick - but is slightly more legit IMO because it adds semantics for humans as well  though it ll keep you from that vaunted 100  code coverage   static void Main String   args      if args Length    0         if Byte TryParse args 0   out maxSize             queue   new Queue   MaxSize   maxSize          else           Environment Exit 0           return             else         Environment Exit 0        return         for Byte j   0  j  lt  queue MaxSize  j         queue Insert j     for Byte j   0  j  lt  queue MaxSize  j         Console WriteLine queue Remove

User · Answer

A couple of different ways to solve the problem   Just replace Environment Exit with return  The compiler knows that return ends the method  but doesn t know that Environment Exit does   static void Main string   args        if args Length    0           if Byte TryParse args 0   out maxSize            queue   new Queue   MaxSize   maxSize          else          return        else          return         Of course  you can really only get away with that because you re using 0 as your exit code in all cases  Really  you should return an int instead of using Environment Exit  For this particular case  this would be my preferred method   static int Main string   args        if args Length    0           if Byte TryParse args 0   out maxSize            queue   new Queue   MaxSize   maxSize          else          return 1        else          return 2            Initialize queue to null  which is really just a compiler trick that says  I ll figure out my own uninitialized variables  thank you very much   It s a useful trick  but I don t like it in this case - you have too many if branches to easily check that you re doing it properly  If you really wanted to do it this way  something like this would be clearer   static void Main string   args      Byte maxSize    Queue queue   null     if args Length    0     Byte TryParse args 0   out maxSize          Environment Exit 0         queue   new Queue   MaxSize   maxSize      for Byte j   0  j  lt  queue MaxSize  j        queue Insert j     for Byte j   0  j  lt  queue MaxSize  j        Console WriteLine queue Remove         Add a return statement after Environment Exit  Again  this is more of a compiler trick - but is slightly more legit IMO because it adds semantics for humans as well  though it ll keep you from that vaunted 100  code coverage   static void Main String   args      if args Length    0         if Byte TryParse args 0   out maxSize             queue   new Queue   MaxSize   maxSize          else           Environment Exit 0           return             else         Environment Exit 0        return         for Byte j   0  j  lt  queue MaxSize  j         queue Insert j     for Byte j   0  j  lt  queue MaxSize  j         Console WriteLine queue Remove

User · Answer

The compiler doesn t know that the Environment Exit   is going to terminate the program  it just sees you executing a static method on a class   Just initialize queue to null when you declare it   Queue queue   null

User · Answer

The compiler doesn t know that Environment Exit   does not return   Why not just  return  from Main

User · Answer

A couple of different ways to solve the problem   Just replace Environment Exit with return  The compiler knows that return ends the method  but doesn t know that Environment Exit does   static void Main string   args        if args Length    0           if Byte TryParse args 0   out maxSize            queue   new Queue   MaxSize   maxSize          else          return        else          return         Of course  you can really only get away with that because you re using 0 as your exit code in all cases  Really  you should return an int instead of using Environment Exit  For this particular case  this would be my preferred method   static int Main string   args        if args Length    0           if Byte TryParse args 0   out maxSize            queue   new Queue   MaxSize   maxSize          else          return 1        else          return 2            Initialize queue to null  which is really just a compiler trick that says  I ll figure out my own uninitialized variables  thank you very much   It s a useful trick  but I don t like it in this case - you have too many if branches to easily check that you re doing it properly  If you really wanted to do it this way  something like this would be clearer   static void Main string   args      Byte maxSize    Queue queue   null     if args Length    0     Byte TryParse args 0   out maxSize          Environment Exit 0         queue   new Queue   MaxSize   maxSize      for Byte j   0  j  lt  queue MaxSize  j        queue Insert j     for Byte j   0  j  lt  queue MaxSize  j        Console WriteLine queue Remove         Add a return statement after Environment Exit  Again  this is more of a compiler trick - but is slightly more legit IMO because it adds semantics for humans as well  though it ll keep you from that vaunted 100  code coverage   static void Main String   args      if args Length    0         if Byte TryParse args 0   out maxSize             queue   new Queue   MaxSize   maxSize          else           Environment Exit 0           return             else         Environment Exit 0        return         for Byte j   0  j  lt  queue MaxSize  j         queue Insert j     for Byte j   0  j  lt  queue MaxSize  j         Console WriteLine queue Remove

User · Answer

The compiler doesn t know that the Environment Exit   is going to terminate the program  it just sees you executing a static method on a class   Just initialize queue to null when you declare it   Queue queue   null

User · Answer

The compiler doesn t know that Environment Exit   does not return   Why not just  return  from Main

User · Answer

The compiler doesn t know that the Environment Exit   is going to terminate the program  it just sees you executing a static method on a class   Just initialize queue to null when you declare it   Queue queue   null

User · Answer

The compiler only knows that the code is or isn t reachable if you use  return   Think of Environment Exit   as a function that you call  and the compiler don t know that it will close the application

[c#] C# error: Use of unassigned local variable

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