Sections with optional counting arguments

Question

I am back for more... =) I am actually trying to fix my own problems, and i feel i learn so much here. Thank you so much for helpin someone as clueless as me ^^

I am attempting to make a text, with a list of tasks. Oppgave in norwegian is the same as task. Each task should have a mandatory argument saying how much points the task is worth. The task, should also have an optional argument alt which will input the task as Alternative 1. Below is a minimal example of what I am looking for

\Oppgave{5}
\Oppgave{3}
\Oppgave{2}
\Oppgave{4}{Alt}
\Oppgave{4}{Alt}
\Oppgave{3}
\Oppgave{7}{Alt}
\Oppgave{7}{Alt}
\Oppgave{7}{Alt}
\Oppgave{9}

The output should look like this

Oppgave 1 (5 poeng)

Oppgave 2 (3 poeng)

Oppgave 3 (2 poeng)

Oppgave 4 Alternative I (4 poeng)

Oppgave 4 Alternative II (4 poeng)

Oppgave 5 (3 poeng)

Oppgave 6 Alternative I (7 poeng)

Oppgave 6 Alternative II (7 poeng)

Oppgave 6 Alternative III (7 poeng)

Oppgave 7 (9 poeng)

Here is a minimal example of my work so far.

\documentclass[10pt,a4paper]{article}
\usepackage[hmargin=3cm,vmargin=3.5cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[norsk]{babel}
\usepackage{amsmath}

\newcounter{problem}
\setcounter{problem}{1}

\newcommand{\oppgave}[1]{\section*{Oppgave \arabic{problem} {\normalfont    \normalsize (#1 poeng)}
\addcontentsline{toc}{section}{Oppgave \arabic{problem} }} \stepcounter{problem} }

\begin{document}

\tableofcontents

\oppgave{3}

\oppgave{4}

\oppgave{2}

\end{document}

Answer 1

You can use the package xparse and to set the last argument as optional. Another method based on the clever idea of egreg (as usual). Instead of using an optional argument you can define a starred version which prints the alternative with a roman numeral instead. Both solution are implemented in the following example. (Thanks to egreg)

\documentclass[10pt,a4paper]{article}
\newcounter{problem}
\setcounter{problem}{0}
\newcounter{alternative}
\setcounter{alternative}{0}
\newif\iffirstalt
\usepackage{xparse}

\NewDocumentCommand{\oppgave}{m o}{%
  \IfNoValueTF{#2}{\setcounter{alternative}{0}\stepcounter{problem}\firstaltfalse}%
                  {\stepcounter{alternative}\iffirstalt\else\stepcounter{problem}\firstalttrue\fi}
  \section*{Oppgave \arabic{problem}%
             {\normalfont\IfNoValueTF{#2}{}{~Alternative \Roman{alternative}\ }
                \normalsize (#1 poeng)}%
   \addcontentsline{toc}{section}{Oppgave \arabic{problem} }} 
}


\NewDocumentCommand{\oppgaveS}{s m}{%
  \IfBooleanTF{#1}%
     {\stepcounter{alternative}\iffirstalt\else\stepcounter{problem}\firstalttrue\fi}%
     {\setcounter{alternative}{0}\stepcounter{problem}\firstaltfalse}%
  \section*{Oppgave \arabic{problem}%
             {\normalfont\IfBooleanTF{#1}{~Alternative \Roman{alternative}\ }{}
                \normalsize (#2 poeng)}%
   \addcontentsline{toc}{section}{Oppgave \arabic{problem} }} 
}
\begin{document}

\tableofcontents

\oppgave{3}

\oppgave{4}

\oppgave{2}[a]

\oppgave{2}[a]


\oppgave{3}

\oppgave{2}[EVERY TEXT WILL BE IGNORED]


\oppgaveS{3}

\oppgaveS{4}

\oppgaveS*{2}

\oppgaveS*{2}

\oppgaveS{3}

\oppgaveS*{2}
\end{document}

Answer 2

Since your alternative problems just need a "stepping" Roman numeral, just declare with * a problem that has alternatives:

\documentclass[a4paper]{article}
\usepackage{xparse}
\newcounter{problem}
\newcounter{alternative}[problem]
\renewcommand{\thealternative}{\Roman{alternative}}

\NewDocumentCommand{\Oppgave}{s m}{%
  \IfBooleanTF{#1}
    {\ifnum\value{alternative}=0 \stepcounter{problem}\fi\stepcounter{alternative}}
    {\setcounter{alternative}{0}\stepcounter{problem}}
  \section*{Oppgave \arabic{problem}\space 
    \ifnum\value{alternative}>0 Alternative \thealternative\space\fi
   {\normalfont\normalsize (#2 poeng)}}
   \addcontentsline{toc}{section}{Oppgave \arabic{problem}} 
}

\begin{document}
\tableofcontents

\Oppgave{5}
\Oppgave{3}
\Oppgave{2}
\Oppgave*{4}
\Oppgave*{4}
\Oppgave{3}
\Oppgave*{7}
\Oppgave*{7}
\Oppgave*{7}
\Oppgave{9}

\end{document}