Pascal - User input name of array
I’m writing a Lazarus application that selects and manipulates data contained in a particular two-dimensional array specified by the user, from a number of preset two-dimensional arrays. My problem is that I don’t know how to convert the user input string into an array name.
An example application contains three two-dimensional arrays:
aaa, bbb and ccc. I want the user to enter, say, bbb and the index (i) in two edit boxes, then be able to read the data contained in bbb[i,2] and bbb[i,3].
...
type
table = array [1..10, 1..3] of real;
var
aaa, bbb, ccc : table;
Duration : real;
i : integer;
Sector : string[3];
...
procedure SetUpTables;
{code that puts data into aaa, bbb, and ccc}
end;
...
{Code that asks user to input aaa, bbb or ccc into Edit1.Text}
...
procedure TForm1.Edit1Exit(Sender: Tobject)
Sector := Edit1.Text;
Duration := Sector[i,3];
end;
...
In the last procedure, I want to use the contents of Sector (aaa, bbb or ccc) to access bbb[i,3]. As you would imagine, I get an “illegal qualifier” error in the line “Duration := Sector[1,3];” at the second index for Sector.
I’m afraid I can’t see how to use the contents of Sector as the array name. I would be grateful for any thoughts on how this can be done.
arrays pascal lazarus
asked Nov 22 '18 at 17:22
tuskerkneetuskerknee
11
add a comment |
I’m writing a Lazarus application that selects and manipulates data contained in a particular two-dimensional array specified by the user, from a number of preset two-dimensional arrays. My problem is that I don’t know how to convert the user input string into an array name.
An example application contains three two-dimensional arrays:
aaa, bbb and ccc. I want the user to enter, say, bbb and the index (i) in two edit boxes, then be able to read the data contained in bbb[i,2] and bbb[i,3].
...
type
table = array [1..10, 1..3] of real;
var
aaa, bbb, ccc : table;
Duration : real;
i : integer;
Sector : string[3];
...
procedure SetUpTables;
{code that puts data into aaa, bbb, and ccc}
end;
...
{Code that asks user to input aaa, bbb or ccc into Edit1.Text}
...
procedure TForm1.Edit1Exit(Sender: Tobject)
Sector := Edit1.Text;
Duration := Sector[i,3];
end;
...
In the last procedure, I want to use the contents of Sector (aaa, bbb or ccc) to access bbb[i,3]. As you would imagine, I get an “illegal qualifier” error in the line “Duration := Sector[1,3];” at the second index for Sector.
I’m afraid I can’t see how to use the contents of Sector as the array name. I would be grateful for any thoughts on how this can be done.
arrays pascal lazarus
asked Nov 22 '18 at 17:22
tuskerkneetuskerknee
11
In Pascal, variable names are discarded durng the compilation process. You need to write a function which accepts the name the user has input and returns the array (or a pointer to it) that (by whatever criteria you choose) matches the name, or some other value (e.g. Nil) if no match is found. You will learn far more if you work out how to do this yourself rather than just have someone post code which does it.
– MartynA
Nov 22 '18 at 17:47
Thanks MartynA. I would like to solve the issue myself, and was thinking about pointers. I’ll carry on trying to resolve it along the lines you suggest.
– tuskerknee
Nov 22 '18 at 17:54
Good. Try your best, and if you get stuck on the coding, by all means come back and post a new q, including your code so far.
– MartynA
Nov 22 '18 at 17:56
add a comment |
I’m writing a Lazarus application that selects and manipulates data contained in a particular two-dimensional array specified by the user, from a number of preset two-dimensional arrays. My problem is that I don’t know how to convert the user input string into an array name.
An example application contains three two-dimensional arrays:
aaa, bbb and ccc. I want the user to enter, say, bbb and the index (i) in two edit boxes, then be able to read the data contained in bbb[i,2] and bbb[i,3].
...
type
table = array [1..10, 1..3] of real;
var
aaa, bbb, ccc : table;
Duration : real;
i : integer;
Sector : string[3];
...
procedure SetUpTables;
{code that puts data into aaa, bbb, and ccc}
end;
...
{Code that asks user to input aaa, bbb or ccc into Edit1.Text}
...
procedure TForm1.Edit1Exit(Sender: Tobject)
Sector := Edit1.Text;
Duration := Sector[i,3];
end;
...
In the last procedure, I want to use the contents of Sector (aaa, bbb or ccc) to access bbb[i,3]. As you would imagine, I get an “illegal qualifier” error in the line “Duration := Sector[1,3];” at the second index for Sector.
I’m afraid I can’t see how to use the contents of Sector as the array name. I would be grateful for any thoughts on how this can be done.
arrays pascal lazarus
asked Nov 22 '18 at 17:22
tuskerkneetuskerknee
11
I’m writing a Lazarus application that selects and manipulates data contained in a particular two-dimensional array specified by the user, from a number of preset two-dimensional arrays. My problem is that I don’t know how to convert the user input string into an array name.
An example application contains three two-dimensional arrays:
aaa, bbb and ccc. I want the user to enter, say, bbb and the index (i) in two edit boxes, then be able to read the data contained in bbb[i,2] and bbb[i,3].
...
type
table = array [1..10, 1..3] of real;
var
aaa, bbb, ccc : table;
Duration : real;
i : integer;
Sector : string[3];
...
procedure SetUpTables;
{code that puts data into aaa, bbb, and ccc}
end;
...
{Code that asks user to input aaa, bbb or ccc into Edit1.Text}
...
procedure TForm1.Edit1Exit(Sender: Tobject)
Sector := Edit1.Text;
Duration := Sector[i,3];
end;
...
In the last procedure, I want to use the contents of Sector (aaa, bbb or ccc) to access bbb[i,3]. As you would imagine, I get an “illegal qualifier” error in the line “Duration := Sector[1,3];” at the second index for Sector.
I’m afraid I can’t see how to use the contents of Sector as the array name. I would be grateful for any thoughts on how this can be done.
arrays pascal lazarus
arrays pascal lazarus
asked Nov 22 '18 at 17:22
tuskerkneetuskerknee
11
asked Nov 22 '18 at 17:22
tuskerkneetuskerknee
11
asked Nov 22 '18 at 17:22
tuskerkneetuskerknee
11
asked Nov 22 '18 at 17:22
tuskerkneetuskerknee
11
asked Nov 22 '18 at 17:22
tuskerkneetuskerknee
11
11
In Pascal, variable names are discarded durng the compilation process. You need to write a function which accepts the name the user has input and returns the array (or a pointer to it) that (by whatever criteria you choose) matches the name, or some other value (e.g. Nil) if no match is found. You will learn far more if you work out how to do this yourself rather than just have someone post code which does it.
– MartynA
Nov 22 '18 at 17:47
Thanks MartynA. I would like to solve the issue myself, and was thinking about pointers. I’ll carry on trying to resolve it along the lines you suggest.
– tuskerknee
Nov 22 '18 at 17:54
Good. Try your best, and if you get stuck on the coding, by all means come back and post a new q, including your code so far.
– MartynA
Nov 22 '18 at 17:56
add a comment |
In Pascal, variable names are discarded durng the compilation process. You need to write a function which accepts the name the user has input and returns the array (or a pointer to it) that (by whatever criteria you choose) matches the name, or some other value (e.g. Nil) if no match is found. You will learn far more if you work out how to do this yourself rather than just have someone post code which does it.
– MartynA
Nov 22 '18 at 17:47
Thanks MartynA. I would like to solve the issue myself, and was thinking about pointers. I’ll carry on trying to resolve it along the lines you suggest.
– tuskerknee
Nov 22 '18 at 17:54
Good. Try your best, and if you get stuck on the coding, by all means come back and post a new q, including your code so far.
– MartynA
Nov 22 '18 at 17:56
In Pascal, variable names are discarded durng the compilation process. You need to write a function which accepts the name the user has input and returns the array (or a pointer to it) that (by whatever criteria you choose) matches the name, or some other value (e.g. Nil) if no match is found. You will learn far more if you work out how to do this yourself rather than just have someone post code which does it.
– MartynA
Nov 22 '18 at 17:47
In Pascal, variable names are discarded durng the compilation process. You need to write a function which accepts the name the user has input and returns the array (or a pointer to it) that (by whatever criteria you choose) matches the name, or some other value (e.g. Nil) if no match is found. You will learn far more if you work out how to do this yourself rather than just have someone post code which does it.
– MartynA
Nov 22 '18 at 17:47
Thanks MartynA. I would like to solve the issue myself, and was thinking about pointers. I’ll carry on trying to resolve it along the lines you suggest.
– tuskerknee
Nov 22 '18 at 17:54
Thanks MartynA. I would like to solve the issue myself, and was thinking about pointers. I’ll carry on trying to resolve it along the lines you suggest.
– tuskerknee
Nov 22 '18 at 17:54
Good. Try your best, and if you get stuck on the coding, by all means come back and post a new q, including your code so far.
– MartynA
Nov 22 '18 at 17:56
Good. Try your best, and if you get stuck on the coding, by all means come back and post a new q, including your code so far.
– MartynA
Nov 22 '18 at 17:56
add a comment |
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In Pascal, variable names are discarded durng the compilation process. You need to write a function which accepts the name the user has input and returns the array (or a pointer to it) that (by whatever criteria you choose) matches the name, or some other value (e.g. Nil) if no match is found. You will learn far more if you work out how to do this yourself rather than just have someone post code which does it.
– MartynA
Nov 22 '18 at 17:47
Thanks MartynA. I would like to solve the issue myself, and was thinking about pointers. I’ll carry on trying to resolve it along the lines you suggest.
– tuskerknee
Nov 22 '18 at 17:54
Good. Try your best, and if you get stuck on the coding, by all means come back and post a new q, including your code so far.
– MartynA
Nov 22 '18 at 17:56