In this guide, you’ll learn how to write for loop in LaTeX using the three most popular packages.
Essential Packages for Writing Algorithms
When writing a research paper, thesis, or report, you often need to present algorithms. LaTeX provides several packages to write pseudocode in a clean, professional way. Among them, the three most widely used are:
algorithmicpackagealgorithm2epackagealgpseudocodepackage (part of algorithmicx)
In this tutorial, you’ll see for loop and nested loop examples with each package.
The algorithmic package
In this package, you can write a loop using the commands \FOR ... \ENDFOR.
\FOR{$i = 1$ to $10$}
\STATE Print $i$
\ENDFOR
\FOR{...} → Inside the braces, you specify the loop condition. For instance, i=1 to 10 means that i will run from 1 to 10.
\STATE → Represents an action or a single step in the algorithm. Here, it tells us to Print i.
\ENDFOR → Marks the end of the loop. It works the same way as curly braces { } in programming.
\documentclass{article}
\usepackage{algorithm}
\usepackage{algorithmic}
\begin{document}
\begin{algorithm}
\caption{Simple for loop Example}
\begin{algorithmic}
\FOR{$i = 1$ to $10$}
\STATE Print $i$
\ENDFOR
\end{algorithmic}
\end{algorithm}
\end{document}
The algorithm2e package
This one is very popular because its syntax looks almost exactly like real programming.
\For{$i \gets 1$ \KwTo $10$}{
Print $i$\;
}
\For{...}{...} → The first {...} defines the loop condition (what the loop runs over), and the second {...} contains the actual body of the loop.
$i \gets 1$ → This means i starts from 1. (Here, \gets is a neat symbol for assignment.)
\KwTo → This means “to,” indicating the range. So the loop continues up to 10.
\; → This is used at the end of each line, just like a semicolon in programming.
{ ... } → Whatever is inside the braces is the loop body.
\documentclass{article}
\usepackage[linesnumbered,ruled,vlined]{algorithm2e}
\begin{document}
\begin{algorithm}
\caption{Example with Algorithm2e}
\For{$i \gets 1$ \KwTo $10$}{
Print $i$\;
}
\end{algorithm}
\end{document}
The algpseudocode package
This package is actually a part of algorithmicx. The code written with it looks much more readable and easy to follow.
\For{$i = 1$ to $10$}
\State Print $i$
\EndFor
\For{...} → This starts the for loop. Here, the condition is written as $i = 1$ to $10$
\State → This is used to describe what action will be performed inside the loop.
\EndFor → This marks the end of the loop.
\documentclass{article}
\usepackage{algorithm}
\usepackage{algpseudocode}
\begin{document}
\begin{algorithm}
\caption{Example with Algpseudocode}
\begin{algorithmic}
\For{$i = 1$ to $10$}
\State Print $i$
\EndFor
\end{algorithmic}
\end{algorithm}
\end{document}
Nested for Loop Example in All Three Packages
A nested loop means running one loop inside another. I’m showing you the syntax of nested loops using three different LaTeX algorithm packages.
% Algorithmic
\FOR{$i = 1$ to $3$}
\FOR{$j = 1$ to $2$}
\STATE Print $i, j$
\ENDFOR
\ENDFOR
% Algorithm2e
\For{$i \gets 1$ \KwTo $3$}{
\For{$j \gets 1$ \KwTo $2$}{
Print $i, j$\;
}
}
% Algpseudocode
\For{$i = 1$ to $3$}
\For{$j = 1$ to $2$}
\State Print $i, j$
\EndFor
\EndFor
Final Note
If you want your research paper/thesis to look professional, pick algorithm2e or algpseudocode. Always keep formatting consistent and avoid mixing packages.
