write a number into a file - pascal

Question

I made a program to put a number in a file. But the file don't show that number(i'mean my code is working but when open the file i created he doesn't show the number.
Here is the code:
Program firstfich;
Uses Wincrt;
Type fich = file Of Integer;
Var f: fich;
x: Integer; {start }
Begin
Assign(f,'C:\a progremming works bac\first bac programe\kill.dat');
Rewrite(f);
x := 47;
Write(f,x);
Close(f);
End.

Answer 1

If you want to see "47" when you open the file in a text editor, you should not create a file containing the byte 47 (which is the ASCII code for the solidus character "/").
Instead, you should create a file containing the bytes 52 and 55, which are the ASCII codes for the characters "4" and "7", respectively.
You should read about how text files are represented in computer memory. See, e.g., the Wikipedia article on character encodings.
Now, to create a file containing the bytes 52 and 55, you just write the string "47" to the file (all code is in Delphi, a modern Pascal implementation -- if you are using some other Pascal implementation, you might need to modify the code slightly):
program Project1;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils;
var
f: text;
begin
try
try
AssignFile(f, 'D:\number.txt');
Rewrite(f);
Write(f, '47');
CloseFile(f);
except
on E: Exception do
Writeln(E.Message);
end;
finally
Writeln('Done.');
Readln;
end;
end.
This will create a file that contains two bytes: 52 and 55. A text editor will display the characters "4" and "7" (assuming ASCII).
On the contrary, if you would create a file that contains only the byte 47, a text editor would display the solidus character ("/", assuming ASCII).
If you want to see the actual bytes in a file, you shouldn't open it in a text editor, but in a hex editor. I encourage you to download a hex editor and play around with these concepts to learn more about them.
Update, in response to comment: If you insist on writing bytes manually, using old Pascal I/O, the following works in Delphi:
program Project1;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils;
var
b: Byte;
f: file;
begin
try
try
AssignFile(f, 'C:\Users\Andreas Rejbrand\Desktop\number.txt');
Rewrite(f, 1);
b := 52; // Or, better: Ord('4')
BlockWrite(f, b, 1);
b := 55; // Or, better: Ord('7')
BlockWrite(f, b, 1);
CloseFile(f);
except
on E: Exception do
Writeln(E.Message);
end;
finally
Writeln('Done.');
Readln;
end;
end.
Still, this is a horrible way of creating a text file containing the number "47"; it should only be considered for educational purposes. To see alternatives to old Pascal I/O, check out https://stackoverflow.com/a/58298368/282848.

Answer 2

program numbertofile;
var
f: TextFile;
x: Integer;
begin
assign(f, 'kill.dat');
rewrite(f);
x := 47;
write(f, x);
close(f);
end.

Answer 3

Just make your file a text file and your integer will be saved in the file the way you expect it to. Just set your file to a text variable like this:
Var f: text;
x: Integer; {start }
Begin
Assign(f,'C:\a progremming works bac\first bac programe\kill.dat');
Rewrite(f);
x := 47;
Write(f,x);
Close(f);
End.
note the write will not put a carriage return or linefeed after the line. if you want numbers on different lines use writeln instead of write.
Writeln(f,x);