D（程式語言）/d2/函式入門

第 3 課：函式入門

在本課中，你將看到更多關於函式的知識，這些函式在第 1 課中已經使用過。如果你已經熟悉其他類似 C 的語言，你只需要快速瀏覽一下即可。

入門程式碼

import std.stdio;

int watch_tv(int first_watched, int then_watched, string channel = "The PHBOS Channel")
{
    writefln("Finished watching %s.", channel);
    return first_watched + then_watched;
}

int commercials(int minutes)
{
    writefln("Watching %s minutes of commercials.", minutes);
    return minutes;
}

int cartoons(int minutes)
{
    writefln("Watching %s minutes of cartoons.", minutes);
    return minutes;
}

void main()
{
    auto minutesoftv = watch_tv(commercials(10), cartoons(30));
    writeln(minutesoftv, " minutes of TV watched!");
}

/*
Output:
  Watching 10 minutes of commercials.
  Watching 30 minutes of cartoons.
  Finished watching The PHBOS Channel.
  40 minutes of TV watched!
*/

概念

函式

函式允許你編寫更結構化的程式碼。使用函式，你可以編寫一些程式碼一次，然後在需要使用該程式碼時隨時呼叫它。

函式語法

讓我們來看看語法

return_type name_of_function(arg1type arg1, arg2type arg2)
{
    // function body code here
    return something;
}