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81 lines
2.8 KiB
ObjectPascal
81 lines
2.8 KiB
ObjectPascal
program testread;
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{uses crt;}
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var
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cadena,cadena2 : string;
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number : real;
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begin
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{clrscr;}
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cadena2 := 'Previous string';
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write ('Enter the string ');
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readln (cadena);
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writeln ('You entered ',cadena);
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writeln ('Previous string was ',cadena2);
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write ('Enter a number ');
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readln (number);
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writeln ('Number entered was ',number);
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readln;
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end.
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{(I have retyped now because my computer is not connected to the net, but I
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think that there are no errors).
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Now you can do some tests:
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1- Compile and run the program as is (that is, using crt). You will find that
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a) the program does not erase the screen (that is normal because we have
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commented clrscr), but the cursor goes to the first line, thus overwriting the
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screen.
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b) While the program is expecting the string to be entered, some of the keys
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do not work correctly: Backspace advances some spaces (just like tab), tab key
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does not work and the cursor keys write garbage. (however this is only in the
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screen, because if you have erased a part of the string it will be actually
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erased).
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c) Once you have press return, the message 'You entered...' appears in the
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same line as the text entered.
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2- Uncomment the clrscr call, cokpile and execute. Point a of test 1 will be
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solved (the screen is erased, so nothing is overwritten), but points b and c
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persist.
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3- Comment 'uses crt' and 'clrscr'. Now you will not be using crt. Now:
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a) Point a of test 1 does not appear: the program begins to write in the
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next line, it does not overwrite anything.
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b) Now all the keys (tab, backspace..) work as expected.
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c) Now the message 'You entered...' appears in the following line, so point
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c of test 1 is also solved.
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d) BUT it writes only 'You entered', WITHOUT writing the string cadena (!).
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It writes also 'Previous string was previous string', so the problem is in
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readln and not in writeln.
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4- To see if the problem is only in the string vars, uncomment the definition
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of number, and also the three lines at the end that deal with number. Now ld
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gives the following error message:
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testread.pp:0 (testread.o): undefined symbol READ_TEXT_INTEGER referenced from
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text segment.
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This error happens with 'uses crt' and also without it.
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5- Define number as word. Regardless of crt we get the following error from ld:
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testread.pp:0 (testread.o): undefined symbol READ_TEXT_WORD referenced from
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text segment.
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6- Uncomment 'uses crt' if it was commented, and change the definition of
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number as real. The program will compile, and it will print the number,
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although in the same line as the input.
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7- Finally, comment 'uses crt' again. This time it will also compile and link,
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but it gives a runtime error!
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Laufzeitfehler 106 bei 66422
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This error is shown before printing the number.
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I expect that these bug report will be useful to debug the RTL. Tonight I will
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try to work in the blockwrite problem.
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Best regards
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Ramon
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--
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}
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