[Tex/LaTex] Change title of appendix in report class

report

I'm writting a report so I use the class 'report' and I would like to include several appendix. For this I use '\appendix'.

My problem is in the result that it gives me to the display at the level of the title of the appendix, for example:

A. Questionnaire.

And I will want to get to the display the title as follows:

Appendix A: Questionnaire

How can I do ?

EDIT

\documentclass[a4paper, 12pt]{report}

% \usepackage[utf8]{inputenc}
% \usepackage[T1]{fontenc}
\usepackage{graphicx}
%Pour les algorithmes
% \usepackage{algorithm}
% \usepackage{algorithmic}
\usepackage[inoutnumbered,ruled,french]{algorithm2e}

\usepackage[french]{babel}
\usepackage[table]{xcolor}
% Pour utiliser les accents
\usepackage[utf8x]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\usepackage{graphicx}
\usepackage{caption}
\usetikzlibrary{spy,calc}

\usepackage{float}
\usepackage{amsmath}
\newcommand{\R}{\mathbf{R}}

\usepackage[colorinlistoftodos]{todonotes}
\usepackage{url}
%pour les informations sur un document compile en pdf et les lien externes/internes
\usepackage{hyperref}
%pour la mise en page des tableaux
\usepackage{array}
\usepackage{tabularx}
%espacement entre les lignes
\usepackage{setspace}

\usepackage{tocloft}

\setlength\cftparskip{-2pt}
\setlength\cftbeforesecskip{-2pt}
\setlength\cftaftertoctitleskip{-2pt}

%police et mise en page du document 

\usepackage[top=2cm, bottom=2cm, left=2cm, right=2cm,]{geometry}
\usepackage{hyperref}

\usepackage[pagestyles]{titlesec}
\titleformat{\chapter}{\normalfont\huge}{\textbf{\thechapter}}{14pt}{\huge\bf}

%\newpagestyle{mystyle}
%{\sethead[\thepage][][\sectiontitle]{}{}{\thepage}}
\usepackage{fancyhdr}
\usepackage{eurosym}
\usepackage{subfig}
% Bibliographie
\usepackage{cite}
\usepackage{multicol}
\usepackage{url}
\newcommand{\Sum}{\ensuremath{\displaystyle\sum}}
\usepackage{amsfonts} % blackboard math symbols
\usepackage{afterpage}
\begin{document}
\chapter{Intoduction}
blabla
\chapter{Experiences}
blabla
\chapter{Results}
blabla
\chapter{conclusion}
blabla
\appendix
\chapter{Questionnaire}
blabla
\chapter{Other Results}
\end{document}

enter image description here

Best Answer

You can obtain this easily with the apptools apckage, which defines the \IfAppendix conditional.

Unrelated: as a general rule, load hyperref as the last package (very few exceptions – most notably cleveref) and the file options of babel as options for the document class, so that all packages which depend on language be aware of the main language of the document. I also simplified the options of geometry: when all margins are equal, you amy just write margin = .... Also, needless to load array if you load tabularx: it loads it for you.

\documentclass[a4paper, 12pt, french]{report}

% \usepackage[utf8]{inputenc}
% \usepackage[T1]{fontenc}
\usepackage{graphicx}
%Pour les algorithmes
% \usepackage{algorithm}
% \usepackage{algorithmic}
\usepackage[inoutnumbered,ruled,french]{algorithm2e}

\usepackage{babel}
\usepackage[table]{xcolor}
% Pour utiliser les accents
\usepackage[utf8x]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\usepackage{graphicx}
\usepackage{caption}
\usetikzlibrary{spy, calc}

\usepackage{float}
\usepackage{amsmath}
\newcommand{\R}{\mathbf{R}}

\usepackage[colorinlistoftodos]{todonotes}
\usepackage{url}
%pour la mise en page des tableaux
\usepackage{tabularx}
%espacement entre les lignes
\usepackage{setspace}

\usepackage{tocloft}

\setlength\cftparskip{-2pt}
\setlength\cftbeforesecskip{-2pt}
\setlength\cftaftertoctitleskip{-2pt}

%police et mise en page du document

\usepackage[margin=2cm,]{geometry}

\usepackage[pagestyles]{titlesec}
\usepackage{apptools}
\titleformat{\chapter}{\normalfont\huge\bfseries}{\IfAppendix{\appendixname\,\thechapter\,:\hspace{-14pt} }{\thechapter}}{14pt}{}

%\newpagestyle{mystyle}
%{\sethead[\thepage][][\sectiontitle]{}{}{\thepage}}
\usepackage{fancyhdr}
\usepackage{eurosym}
\usepackage{subfig}
% Bibliographie
\usepackage{cite}
\usepackage{multicol}
\usepackage{url}
\newcommand{\Sum}{\ensuremath{\displaystyle\sum}}
\usepackage{amsfonts} % blackboard math symbols
\usepackage{afterpage}
%pour les informations sur un document compile en pdf et les lien externes/internes
\usepackage{hyperref}

\begin{document}

\chapter{Introduction}
blabla
\chapter{Experiences}
blabla
\chapter{Results}
blabla
\chapter{Conclusion}
blabla
\appendix
\chapter{Questionnaire}
blabla
\chapter{Other Results}

\end{document}

enter image description here

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