How do I change a font document wide?

Question

How do I change a font for a latex document?

I am using the \documentclass{article}, which sets the document in a serif font. I also declared \usepacke{helvet}, since thats the font I would like to use as a sans-serif. But how do I get latex to actually set the document in a sans-serif font?

Also, I am using the package lslisting to format code-listings. How can I set my document,so that all code is set in a separate font, e.g. courier or any other typewriter font?

Answer 1

You want to change the default family to be the sans serif family.

\renewcommand\familydefault{\sfdefault}

does exactly that.

Concerning your other question,

\lstset{basicstyle=\ttfamily}

make all code to be typeset in the active typewriter family, which is by default Computer Modern Typewriter. You can change that to Courier with \usepackage{courier}, just as you select Helvetica for the sans family with \usepackage{helvet}.