Question

制作唱片节目，我有点卡住了。

program myMusicPlayer;
uses TerminalUserInput, SysUtils;

type
genreType = (Comedy, Punk, Metal);


album = record
    albumName : String;
    artistName : String;
    genre : genreType;
    tracks : array [0..4] of String;
    location: array [0..4] of String;
end;

function readGenre(prompt: String): genreType;
var
val : Integer;

begin
WriteLn('1 - Comedy');
WriteLn('2 - Punk');
WriteLn('3 - Metal');
val := ReadInteger(prompt);

while ((val < 1) or (val > 3)) do
begin
    WriteLn('Please enter a value between 1 & 3');
    val := ReadInteger(prompt);
end;

result := genreType(val-1);
end;

function readAlbum(const alb : album): album;
var
i: Integer;

begin
result.albumName := ReadString('Enter album name here: ');
result.artistName := ReadString('Enter artist name here: ');
result.genre := readGenre('Enter genre here: ');

for i := 0 to 4 do
begin
    result.tracks[i] := ReadString('Enter track list here: ');
end;
for i := 0 to 4 do
begin
result.location[i] := ReadString('Enter file location here: ');
end;
end;

procedure printAlbum(const toPrint: album);
var
i : Integer;

begin
WriteLn('Album title: ', toPrint.albumName);
WriteLn('Artist name: ', toPrint.artistName);
WriteLn('Genre: ', toPrint.genre);

for i := 0 to 4 do
begin
    WriteLn('Track ', i, ' is: ', toPrint.tracks[i]);
    WriteLn('File ', i, ' location is: ', toPrint.location[i]);
end;
end;

此过程“runAlbum”正在发生问题，我尝试使用此功能，以便用户可以选择1到4之间的数字来选择他们之前输入的相应曲目。

procedure runAlbum(prompt: String; min, max: Integer);
var
result : Integer;

begin
result := ReadInteger(prompt);
while ((result < min) or (result > max)) do
begin
    WriteLn('Please select a track between', min, ' and ', max, ' to play: 
');
    result := ReadInteger(prompt);
end;
end;

但是我不清楚我需要在runAlbum旁边的括号中输入什么参数来运行程序，现在我尝试的所有内容都运行错误“为”runAlbum“设置的参数数量错误”

procedure Main();
var
newAlbum : album;

begin
newAlbum := readAlbum(newAlbum);
printAlbum(newAlbum);
runAlbum(); 
end;

begin
Main();
end.

Answer 1

当您致电runAlbum时，您必须为其声明中指定的每个参数提供值（即参数），即Prompt，min和max。目前，您没有证明任何参数值，因为您的呼叫中有空括号。

所以你应该用类似

的方式来调用它

runAlbum(newAlbum.albumName +': enter a track number to play', 0, 99);

当然，值0和99应替换为newAlbum可用的最低和最高数字。我假设您将能够找出如何从专辑数据中提供相关值。

Pascal - 参数数量错误

1 个答案: