I'm trying to do a program that reads numbers from a file, outputs them into a vector and then writes them. The code compiles nicely, but when run, it gets stuck with just a prompt without delivering any output.
Program LectorDeEnteros;
type
Arreglo = array [1..30] of integer;
var
//Arch:text;
Prom:byte;
i:integer;
ArregloA:Arreglo;
Procedure CargadorVectorialdeArchivo (var ArregloA:Arreglo);
var
Arch:text;
i:integer;
Begin
assign (Arch,'Numeros.txt');
reset (Arch);
i := 1;
while not eof(Arch) do
Write(Arch);Read(ArregloA[i]);
i := i + 1;
End;
Begin
CargadorVectorialdeArchivo(ArregloA);
for i := 1 to 14 do
WriteLn(ArregloA[i]:3);
End.
As i said, there are no error messages, just the prompt and no output. I have to CTRL-Z to get it out of this "loop". The expected output would be the numbers of the array, one on each line.
Rewrite the procedure as this:
Procedure CargadorVectorialdeArchivo (var ArregloA:Arreglo);
var
Arch:text;
i:integer;
Begin
assign (Arch,'Numeros.txt');
reset (Arch);
i := 1;
while not eof(Arch) do
begin
Read(Arch,ArregloA[i]);
i := i + 1;
end;
End;
Putting Arch in front of the file tells the compiler that you want to read the contents from that file, not from the keyboard.
Related
Im having problems with this code, I have two file of char, one is filed with information about books, and the other is empty, i have to write in SAL some information from S and then show the total of how many books match the first 2 digits of the code and how many are R and how many are T. The code, does write the information form S to Sal, but when its supposed to show the totals it appears ERORR 100 on screen. I read about it and it says that it is a problem with 'Disk read error' and that *This error typically occurs, if you "seed" a non-existent record of a typed file and try to read/write it. *, i really dont undertand.
I've benn trying to figure it out, but I haven't been able to. I notice that if I dont put 'WHILE NOT EOF(S) DO' the error does not appear, but of course i need the while, if someone is able to point out my mistakes i would really apreciate it.
This is the code:
uses crt;
var
i : byte;
s,sal: file of char;
v,l1,l2: char;
cs,cn,cl: integer;
pn,ps,tot: integer;
BEGIN
cs:=0; cn:=0; i:=0; cl:=0;
Assign (s, 'C:\Users\te\Documents\s.txt');
{$I-}
Reset (s);
{$I+}
if IOResult <> 0 then
begin
writeln('Error');
halt(2);
end;
Assign (sal, 'C:\Users\te\Documents\sal.txt');
{$I-}
Rewrite (sal);
IOResult;
{$I+}
if IOResult <> 0 then
halt(2);
writeln('Please write the code of the book, only 2 digits');
read(L1);read(L2);
read(s,v);
while (not eof(s)) do
begin
for i:=1 to 2 do
read(s,v);
if (v = '0') then
begin
read(s,v);
if (v = '1') or (v = '2') then
begin
for i:=1 to 5 do
read(s,v);
if (v = 'R') then
begin
read(s,v);
cs:= cs + 1;
end
else
begin
if (v = 'T') then
begin
cn:= cn + 1;
read(s,v);
end;
end;
while (v <> '-') do
read(s,v);
while (v = '-') do
read(s,v);
if (v = L1) then
begin
write(sal, v);
read(s,v);
if (v = L2) then
begin
write(sal,v);
read(s,v);
cl:= cl + 1;
end;
end;
while ( v <> '/') do
begin
write(sal,v);
read(s,v);
end;
write(sal, '-');
end
else
begin
for i:= 1 to 5 do
read(s,v);
if (v = 'R') then
cs:= cs + 1
else
cn:= cn + 1;
if (v = L1) then
read(s,v);
if (v = L2) then
begin
cl:= cl + 1;
read(s,v);
end;
end;
end
else
begin
for i:= 1 to 5 do
read(s,v);
if (v = 'R') then
cs:= cs + 1
else
cn:= cn + 1;
if (v = L1) then
read(s,v);
if (v = L2) then
begin
cl:= cl + 1;
read(s,v);
end;
end;
end;
tot:= cs + cn;
ps:= (cs * 100) div tot;
pn:= (cn * 100) div tot;
writeln('TOTAL ',cl);
writeln();
writeln(ps,'% and',pn,'%');
The file S content:
02022013Rto kill a mockingbird-1301/02012014Tpeter pan-1001/02032013Thowto-2301/02012012Tmaze runner-1001/02012012Tmaze runner-1001/02012012Tmaze runner-1001/$
I really just need someone else's point of view on this code, I think maybe the algorithm is flawed.
Thanks
(After your edit, i see that your code now compiles w/o error in FPC, so I'm glad you've managed to fix the error yourself)
As this is obviously coursework, I'm not going to fix your code for you and in any case the wayEven so, I'm afraid you are going about this is completely wrong.
Basically, the main thing wrong with your code is that you are trying to control what happens as your read the source file character by character. Quite frankly, that's a hopeless way of trying to do it, because it makes the execution flow unnecessarily complicated and littered with ifs, buts and loops. It also requires you to keep mental track of what you are trying to do at any given step, and the resulting code is inherently not self-documenting - imagine if you came back to your code in six months, could you tell at a glance how it works and what it does? I certsinly couldn't personally.
You need to break the task down in a different way. Instead of analysing the problem from the bottom up ("If I read this character next, then what I need to do next is ...') do it from the top down: Although your input file is a file of char, it contains a series of strings, separated by a / character and finally terminated by a $ (but this terminator does not really matter). So what you need to do is to read these strings one-by-one; once you've got one, check whether it's the one you're looking for: if it is. process it however you need to, otherwise read the next one until you reach the end of the file.
Once you have successfully read one of the book strings, you can then split it up into the various fields it's composed of. The most useful function for doing this splitting is probably Copy, which lets you extract substrings from a string - look it up in the FPC help. I've included functions ExtractTitle and ExtractPreamble which show you what you need to do to write similar functions to extract the T/R code and the numeric code which follows the hyphen. Btw, if you need to ask a similar q in the future, it would be very helpful if you include a description of the layout and meaning of the various fields in the file.
So, what I'm going to show you is how to read the series of strings in your S.Txt by building them character-by-character. In the code below, I do this using a function GetNextBook which I hope is reasonable self-explanatory. The code uses this function in a while loop to fill the BookRecord string variable. Then, it simply writes the BookRecord to the console. What your code should do, of course, is to process the BookRecord contents to see if it is the one you are looking for and then do whether the remainder of your task is.
I hope you will agree that the code below is a lot clearer, a lot shorter and will be a lot easier to extend in future than the code in your q. They key to structuring a program this way is to break the program's task into a series of functions and procedures which each perform a single sub-task. Writing the program that way makes it easier to "re-wire" the program to change what it does, without having to rewrite the innards of the functions/procedures.
program fileofcharproject;
uses crt;
const
sContents = '02022013Rto kill a mockingbird-1301/02012014Tpeter pan-1001/02032013Thowto-2301/02012012Tmaze runner-1001/02012012Tmaze runner-1001/02012012Tmaze runner-1001/$';
InputFileName = 'C:\Users\MA\Documents\S.Txt';
OutputFileName = 'C:\Users\MA\Documents\Sal.Txt';
type
CharFile = File of Char; // this is to permit a file of char to be used
// as a parameter to a function/procedure
function GetNextBook(var S : CharFile) : String;
var
InputChar : Char;
begin
Result := '';
InputChar := Chr(0);
while not Eof(S) do begin
Read(S, InputChar);
// next, check that the char we've read is not a '/'
// if it is a '/' then exit this while loop
if (InputChar <> '/') then
Result := Result + InputChar
else
Break;
end;
end;
function ExtractBookTitle(BookRecord : String) : String;
var
p : Integer;
begin
Result := Copy(BookRecord, 10, Length(BookRecord));
p := Pos('-', Result);
if p > 0 then
Result := Copy(Result, 1, p - 1);
end;
procedure AddToOutputFile(var OutputFile : CharFile; BookRecord : String);
var
i : Integer;
begin
for i := 1 to Length(BookRecord) do
write(OutputFile, BookRecord[i]);
write(OutputFile, '/');
end;
function ExtractPreamble(BookRecord : String) : String;
begin
Result := Copy(BookRecord, 1, 8);
end;
function TitleMatches(PartialTitle, BookRecord : String) : Boolean;
begin
Result := Pos(PartialTitle, ExtractBookTitle(BookRecord)) > 0;
end;
var
i : Integer; //byte;
s,sal: file of char;
l1,l2: char;
InputChar : Char;
BookFound : Boolean;
cs,cn,cl: integer;
pn,ps,tot: integer;
Contents : String;
BookRecord : String;
PartialTitle : String;
begin
// First, create S.Txt so we don't have to make any assumptions about
// its contents
Contents := sContents;
Assign(s, InputFileName);
Rewrite(s);
for i := 1 to Length(Contents) do begin
write(s, Contents[i]); // writes the i'th character of Contents to the file
end;
Close(s);
cs:=0; cn:=0; i:=0; cl:=0;
// Open the input file
Assign (s, InputFileName);
{$I-}
Reset (s);
{$I+}
if IOResult <> 0 then
begin
writeln('Error');
halt(2);
end;
// Open the output file
Assign (sal, OutputFileName);
{$I-}
Rewrite (sal);
IOResult;
{$I+}
if IOResult <> 0 then
halt(2);
// the following reads the BookRecords one-by-one and copies
// any of them which match the partial title to sal.txt
writeln('Enter part of a book title, followed by [Enter]');
readln(PartialTitle);
while not Eof(s) do begin
BookRecord := GetNextBook(S);
writeln(BookRecord);
writeln('Preamble : ', ExtractPreamble(BookRecord));
writeln('Title : ', ExtractBookTitle(BookRecord));
if TitleMatches(PartialTitle, BookRecord) then
AddToOutputFile(sal, BookRecord);
end;
// add file '$' to sal.txt
write(sal, '$');
Close(sal);
Close(s);
writeln('Done, press any key');
readln;
end.
Im very new to using files and im really struggling to fix this any help would be great.
It seems that the error is coming from my read array function but not entirely
sure i am also not to sure what the 104 error really means
thanks in advance
program ReadFromFile;
type
lineArray = array [0..19] of String;
procedure PrintArray(lines: lineArray);
var
i: Integer;
begin
for i:=0 to High(lines) do
begin
WriteLn('Text is: ', lines[i], ' Line number is: ', i);
end;
end;
function ReadArray(var myFile: TextFile):lineArray;
var
count : Integer;
lines : lineArray;
i: Integer;
begin
ReadLn(myFile, count);
for i := 0 to count do
begin
ReadLn(myFile, lines[i]);
end;
result := lines;
end;
procedure Main();
var
myFile: TextFile;
line: lineArray;
begin
AssignFile(myFile, 'mytestfile.dat');
ReWrite(myFile);
line:=ReadArray(myFile);
Close(myFile);
AssignFile(myFile, 'mytestfile.dat');
Reset(myFile);
PrintArray(line);
Close(myFile);
end;
begin
Main();
end.
You don't know what that error means. Neither do I off the top of my head. So, let's look it up in the documentation and find out. Websearch takes us here: https://www.freepascal.org/docs-html/user/userap4.html
File not open for input
Reported by Read, BlockRead, Eof, Eoln, SeekEof or SeekEoln if the file is not opened with Reset.
You have your calls to open the file the wrong way round. Call Reset to open for reading, Rewrite to open for writing.
Notes:
Looping from 0 to count will perform count + 1 iterations. I'd expect to see you looping from 0 to count - 1.
You don't check whether your array is long enough. You therefore run the risk of a buffer overrun. A dynamic array would avoid this.
It's not clear why you open the file for a second time when you print the contents to the console.
You could have looked up the error code yourself. Please take the hint to do web search the next time you encounter an error like this.
I want to capture cmd.exe output and show it in a diffrent gui I am making. I want to make a command interpreter with extended functionality. The dir command works flawless, the problem ocurrs when I try to execute another process like ipconfig.
I don't see ipconfig output. Is there a workarround on that ?!
I use TProcess component from Lazarus (FreePascal)
proc := TProcess.Create(nil);
proc.Options:= [poUsePipes, poNoConsole];
proc.ShowWindow:= swoHIDE;
proc.Executable:= 'cmd';
Reading output thread:
if (Length(cmd) > 0) then
begin
cmd := cmd + #13#10;
proc.Input.Write(cmd[1], Length(cmd)); // here I write command from user
strikes := 0;
end
else
if proc.Output.NumBytesAvailable > 0 then
begin
while proc.Output.NumBytesAvailable > 0 do
begin
FillChar(buf, sizeof(buf), #0);
proc.Output.Read(buf, sizeof(buf) - 1);
data := data + buf;
end;
// data gets echoed to user
It works fine for me (I use FPC 3.1.1 & Lazarus 1.5 but I hope it does not matter):
proc.Options:= [poUsePipes];
proc.ShowWindow:= swoHIDE;
proc.Executable:= 'cmd';
...
procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
var
cmd: String;
begin
if Key = #13 then
begin
Key := #0;
if not proc.Active then
proc.Active := True;
cmd := Edit1.Text + LineEnding;
proc.Input.Write(cmd[1], Length(cmd));
end;
end;
procedure TForm1.Timer1Timer(Sender: TObject);
var
buf: array[0..65535] of Char;
begin
if proc.Output.NumBytesAvailable > 0 then
begin
while proc.Output.NumBytesAvailable > 0 do
begin
FillChar(buf, sizeof(buf), #0);
proc.Output.Read(buf, sizeof(buf) - 1);
Memo1.Lines.Add(buf);
end;
end;
end;
I guess that you just does not catch process output properly.
Good luck.
PS: If you need to create some windows console-like application, the best way, I think, is using Windows console API instead of cross-platform Lazarus components.
PPS: To emulate console look and behavior with Lazarus use CmdLine component.
In general it is smart to first check if the short examples don't solve the problem:
e.g.
uses process;
var s : ansistring;
begin
runcommand('ipconfig',['/all'],s);
writeln(s);
end.
works fine, and saves a whole lot of trouble. (FPC 2.6.2+ though)
I am attempting to write a comment stripper in pascal. I run my code and pass it a C source code file and it strips the comments from the file and prints the result to terminal.
I am fairly new to pascal. I am getting some very strange output and I cannot figure out why. The code checks for comments line by line and prints characters one at a time. The comment stripper is printing what seems to be random characters whenever it reaches the start of a new line. I am using pascals Write(Str[i]) function to print characters and WriteLn() once the end of a line is reached.
I have no idea why im receiving weird output. I am running Linux Mint and can compile and run my code, but I receive this strange output. I also tried running my code on a Mac and received a run-time error:
Program Path: ./Assignment1
File Name: lol.c
Runtime error 2 at $00011532
$00011532
$0002F7F6
$000113FD
$00011328
$00000002
Here is my code
program Assignment1;
uses
Sysutils;
var UserFile : TextFile;
TString : String;
OLine : String;
i : integer;
isComment : boolean;
skip : boolean;
begin
{$I+}
WriteLn('Program Path: ', ParamStr(0));
WriteLn('File Name: ', ParamStr(1));
Assign(UserFile, ParamStr(1) + '.c');
Reset(UserFile);
isComment := false;
skip := true;
Repeat
Readln(UserFile, TString);
for i:= 0 to ((Length(TString) - 1)) do
begin
if(skip) then
begin
skip := false;
continue;
end;
if(isComment = false) Then
begin
if(TString[i] = '/') Then
begin
if(TString[i+1] = '/') Then
begin
break;
end
else if(TString[i+1] = '*') Then
begin
isComment := true;
skip := true;
continue;
end;
end;
Write(TString[i]);
if(i = Length(TString) - 1) Then
begin
Write(TString[i + 1]);
end;
end
else
begin
if(TString[i] = '*') Then
begin
if(TString[i + 1] = '/') Then
begin
isComment := false;
skip := true;
continue;
end;
end;
end;
end;
WriteLn();
Until Eof(UserFile);
end.
I receive random characters which range from standard keyboard symbols to unicode blocks such as the ones found here.
Does anyone have any suggestions?
As 500 - Internal Server Error says, Pascal strings are 1-based. Your references to slot zero are returning garbage. If these are 256-byte strings you're getting the length code, I don't recall the memory layout of the pointer-based strings to know what you're getting in that case. You're also losing the last character of every string because of this.
Beyond that I see a definite bug: Look at what happens with a line ending in /
I also do not understand this:
if(i = Length(TString) - 1) Then
begin
Write(TString[i + 1]);
end;
It seems to me it's writing an extra character but I'm not sure.
1.this is my code i want to read a record from a text file into array in pascal my program is about making a hotel helper and i already have a text file with the data of the hotel then i should read it from the text file and store it in array .. but i am facing error 103 exit code (file not open).... any help Please . :)
program Hotel1(input,output);
const max =10; MaxFloor =10;
type
Date = record
day :1..31;
month:1..12;
year:integer;
end;
Booking = record
Guest:string[20];
S_Date:date;
E_date:date;
end;
Booking_Mat= array[1..max] of Booking;
History_Booking = record
B_num:integer;
B_Mat:Booking_Mat;
end;
Room = record
Num:integer;
Bed_num:integer;
Price:integer;
Status:Boolean;
H:History_Booking;
end;
Data = record
Ro:Room;
m:integer;
end;
Data_mat= array [1..max] of Data;
Procedure Read_Data(filename:string; var table:Data_mat);
var df:text; i,j :integer;
n,m,num,GN:integer;
Bed_num,Price:integer;
f:text;
s,e:Date;
Gname:string[20];
ok:boolean;
a:Data_mat;
c:char;
Begin
writeln('Reading ',filename,' records into array.... ');
assign(df,filename);
reset(df);
i:=0;
while (not eof) do
begin
i:=i+1;
Read (f,num);
a[i].Ro.num:=num;
Read (f,Bed_num);
a[i].Ro.Bed_num:=Bed_num;
Read (f,Price);
a[i].Ro.Price:=Price;
Read(f,c);
if (c ='Y') then
a[i].Ro.status:= true
else
a[i].Ro.status:= false;
readln;
End; {while eof}
close(df);
End; {Read_Data}
You've declared two variables of type Text, (df and f) in your var block.
You open df with these lines:
assign(df,filename);
reset(df);
You then read from f (which is not the file you opened above) in several lines, such as this one:
Read (f, num);
It's interesting to note that you actually manage to close the file you really opened, even though you never use it in your loop:
close(df);
The solution to all of these issues is to delete the declaration of either f or df, and then fix the compiler errors you get by correcting the code to use the remaining text variable. (Two important lessons here are
Only declare the variables you actually need.
Use the variables you declare.
Your loop is also invalid, because you're using while not eof with no file provided for which to test the end. Your loop should read while not Eof(df) do instead.
It's also much better to follow the typical naming convention of prefixing types with a T. It makes it clear that it's a type and not a variable, and allows you to read the code more easily. For instance, I'd change your definition of Data to TRoomData, and change the other type declarations accordingly. Here's an example - note that TRoomData now has a field (member) named Room of type TRoom:
TRoomData = record
Room: TRoom;
m: Integer;
end;
TRoom is defined as
TRoom = record
Num: Integer;
Bed_num: Integer;
Price: Integer;
Status: Boolean;
H: THistory_Booking;
end;
And so forth. This allows you to write code more clearly:
var
RoomData: TRoomData;
begin
RoomData.Room.Num := 1;
RoomData.Room.Price := 50;
// etc.
end;
With all that being said, your file does not contain text, and therefore you're using the wrong file type by using df: Text in the first place. You should use a File of TRoomData, allowing you to read and write entire records at a time. Here's an example of doing so:
var
DF: File of TRoomData;
RoomData: TRoomData;
i: Integer;
const
DataFileName = 'D:\TempFiles\RoomData.dat';
Writing it:
// Put some data into the record
RoomData.Room.Num := 1;
RoomData.Room.Bed_num := 1;
RoomData.Room.Price := 40;
RoomData.Room.Status := True;
RoomData.Room.H.B_num := 1;
for i := 1 to Max do
begin
RoomData.Room.H.B_Mat[1].Guest := Format('Guest %d', [i]);
RoomData.Room.H.B_Mat[1].S_Date.Year := 2014;
RoomData.Ro.H.B_Mat[1].S_Date.Month := i;
RoomData.Ro.H.B_Mat[1].S_Date.Day := i;
end;
// Write it out to the file
AssignFile(DF, DataFileName);
try
Rewrite(DF);
Write(DF, RoomData);
finally
CloseFile(DF);
end;
Reading it back in:
AssignFile(DF, DataFileName);
try
Reset(DF);
Read(DF, RoomData);
finally
CloseFile(DF);
end;
(Or, better yet: If the version of Pascal you're using supports it, move away from the old file I/O routines and start using TFileStream instead.)
Last but not least, learn to properly format your code. It makes it much easier to debug and maintain, and it's much easier to read when you can follow the execution path clearly.