代码没有移动过去阅读

Question

我的代码有问题。它开始很好，但是当开始要求从用户那里获取输入时，它不会移动到 if 语句。我怎样才能解决这个问题。我试过堆来解决这个问题并最终让它读取数据但不断说它无效。

PROGRAM AT3 (input, output);
uses crt, math;
CONST
    band6 = 90;
    band5 = 80;
    band4 = 70;
    band3 = 60;
    band2 = 50;
VAR
    Studname : array of string;
    studmark : array of integer;
    flag : boolean;
    studinfo : text;
    input : string;
    count : integer;
    num : integer;
        input2: integer;
    highmark, lowmark : integer;
    median, average : integer;

BEGIN
    lowmark := 100;
    highmark := 0;
    median := 0;
    ASSIGN (Studinfo, 'ExamResults.txt');
    flag := false;
    WRITELN('welcome to the Band generator.');
        WRITELN('To enter student results, please enter the number of students. To see class statistics, please type zzz. To clear the screen type clear screen. And to exit the program, type exit');
    While flag = false DO
        ReadLN (input);
        IF input = 'zzz' THEN
            WHILE not EOF(Studinfo) DO
            BEGIN
                WRITELN(studinfo);
            END;
        IF input = 'exit' THEN
            Flag := true;
                IF input = 'clear screen' THEN
                        CLRSCR
                ELSE
                    if input2 <> 0 THEN
                        num := input2
                ELSE
                WRITELN('Please enter a valid number.');
        FOR count := 0 to num-1 DO
            BEGIN
            WRITELN('Please enter name of student', count);
            read(studname[count]);
            WRITE(studinfo, studname[count]);
            WRITELN('Please enter mark of student', count, 'out of 100 (nearest whole number)');
            read(studmark[count]);              write(studinfo, studmark[count]);
            IF studmark[count] >=band6 THEN
                WRITELN(studinfo, 'band6');
            IF studmark[count] >=band5 THEN
                WRITELN(studinfo, 'band5');
            IF studmark[count] >=band4 THEN
                WRITELN(studinfo, 'band4');
            IF studmark[count] >=band3 THEN
                WRITELN(studinfo, 'band3');
            IF studmark[count] >=band2 THEN
                WRITELN(studinfo, 'band2');
            IF studmark[count] <band2 THEN
                WRITELN(studinfo, 'band1');
            IF studmark[count] >= highmark THEN
                highmark := studmark[count];
            IF studmark[count] <= lowmark THEN
                lowmark := studmark[count];
            END;
        median := highmark MOD 2;

    CLOSE(studinfo);
END.

Answer 1

看看你的台词：

While flag = false DO
        ReadLN (input);

Flag 永远不会为 false，因此它会永远读取。您的 begin/end 块有问题。

Answer 2

像这样的问题经常会引起评论，例如“SO is not a homework-doing 服务。”这个问题有点特别，因为我想不出有礼貌的方式的来形容它。它具有由某人写的所有迹象真的不知道他们在做什么 - 但不要绝望，我们都曾经是初学者！

我不会为你重写你所有的代码——因为你不会从中学到任何东西——但下面至少应该给出你是一个功能性的主循环，然后你可以自己完成并根据需要进行修饰。

我修复的主要问题是循环中的动作顺序——原来的委婉地说，完全是一团糟。我添加了用大括号 {} 括起来的各种注释。最近有一种评论风格使用//但我不知道是什么风格您正在使用的 Pascal。

代码：

const
    band6 = 90;
    band5 = 80;
    band4 = 70;
    band3 = 60;
    band2 = 50;
    ArraySize = 20;  { to set explicit array sizes }
var
    studname : array[1..ArraySize] of string;
    studmark : array[1..ArraySize] of integer;
    flag : boolean;
    studinfo : text;
    kbdinput : string; { to avoid name clash with program Input param}
    count : integer;
    num : integer;
    {input2: integer; not used}
    highmark,
    lowmark : integer;
    median, average : integer;

begin
    lowmark := 100;
    highmark := 0;
    median := 0;
    assign (studinfo, 'c:\temp\examresults.txt'); { always use full path for file name }
    Rewrite(studinfo);  { set studinfo in the state to allow writing to the file}

    flag := false;
    writeln('welcome to the band generator.');
        writeln('to enter student results, please enter the number of students when prompted.');
    while flag = false do
    begin
        write('please enter a valid number of students. ');
        readln(num);
        for count := 1 to num do { not change of start and stop values}
        begin
          write('please enter name of student #', count, ' followed by [Enter] ');
          readln(studname[count]);
          write(studinfo, studname[count]);

          write('please enter mark of student #', count, ' out of 100 (nearest whole number) followed by [Enter] ');
          readln(studmark[count]);
          write(studinfo, studmark[count]);
        end;
{
            if studmark[count] >=band6 then
                writeln(studinfo, 'band6');
            if studmark[count] >=band5 then
                writeln(studinfo, 'band5');
            if studmark[count] >=band4 then
                writeln(studinfo, 'band4');
            if studmark[count] >=band3 then
                writeln(studinfo, 'band3');
            if studmark[count] >=band2 then
                writeln(studinfo, 'band2');
            if studmark[count] <band2 then
                writeln(studinfo, 'band1');
            if studmark[count] >= highmark then
                highmark := studmark[count];
            if studmark[count] <= lowmark then
                lowmark := studmark[count];
            end;
        median := highmark mod 2;
}

      writeln('to see class statistics, please type zzz. to clear the screen type zzz and to exit the program, type exit');
      readln (kbdinput);
      if kbdinput = 'zzz' then
      {  The following does nothing useful
          while not eof(studinfo) do
          begin
              writeln(studinfo);
          end;
      }
      ;
      if kbdinput = 'exit' then
          flag := true
      else
        if kbdinput = 'clear screen' then
          {clrscr;'}

      close(studinfo);
    end;
end.

代码没有移动过去阅读

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