How to define line behaviour in Tikz?

Question

I have the following LaTex code:

% !TEX TS-program = pdflatex
% !TEX encoding = UTF-8 Unicode
\documentclass[14pt, a4paper]{article} % use larger type; default would be 10pt
\usepackage[utf8]{inputenc}
\usepackage[russian]{babel}
\usepackage{listings}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows}
\usetikzlibrary{shapes.multipart}

\oddsidemargin=-15.4mm
\textwidth=190mm
\headheight=-32.4mm
\textheight=277mm
\tolerance=100
\parindent=0pt
\parskip=8pt
\pagestyle{empty}


\tikzstyle{startstop} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black, fill=blue!50]

\tikzstyle{io} = [trapezium, trapezium left angle=70, trapezium right angle=110, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=red!50]

\tikzstyle{process} = [rectangle, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=gray!50]

\tikzstyle{decision} = [diamond, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=green!50]

\tikzstyle{loop} = [rectangle split, rectangle split parts=2,draw, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=gray!50]

\tikzstyle{arrow} = [thick,->,>=stealth]



\begin{document}
    {\textbf{Задача 1.}}
    \\
    Схема алгоритма:
    \\
    \begin{center}
        \begin{tikzpicture}[node distance=2cm]
            \node (start) [startstop] {Начало};
            
            \node (input) [io, below of=start] {Ввод n};
            
            \node (ds1) [decision, below of=input, yshift=-0.4cm]{n = 0?};
            
            \node (y-case) [process, right of=ds1, xshift=2cm]{pow = 1};
            
            \node (while) [loop, below of=ds1, yshift=-0.4cm]{ 
                \nodepart{one} While n > 0 
                \nodepart{two} 
                    \begin{tabular}{cc}
                         n = n //10 \\
                         pow = pow +1 \\
                    \end{tabular}
                };
            
            \node (output) [io, below of=while, ]{Вывод pow};
            
            \node (stop) [startstop, below of=output] {Конец программы};
            
            \draw[arrow] (start) -- (input);
            \draw[arrow] (input) -- (ds1);
            \draw[arrow] (ds1) -- node[anchor=south]{Yes}(y-case);
            \draw[arrow] (y-case) |- (while);
            \draw[arrow] (ds1) -- node[anchor=east]{No}(while);
            \draw[arrow] (while) -- (output);
            \draw[arrow] (output) -- (stop);
        \end{tikzpicture}
    \end{center}

\end{document}

And it's built to this:

How can I define the behavior of the "NO" arrow to make it go from the left corner of the diamond block (now it goes from the bottom corner)?

Answer 1

Like this?

\documentclass[12pt, a4paper]{article} 
\usepackage[russian]{babel}
\usepackage{listings}

\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                chains,       % new
                positioning,  % new
                quotes,       % new
                shapes.geometric,
                shapes.multipart,
                babel
                }

\oddsidemargin=-15.4mm % for this settings is better to use >"geometry" package
\textwidth=190mm
\headheight=-32.4mm
\textheight=277mm
\tolerance=100
\parindent=0pt
\parskip=8pt
\pagestyle{empty}


\makeatletter
\tikzset{FlowChart/.style={  % <--- corrected, new
     base/.style = {draw,
                    minimum width=3cm, minimum height=1cm, align=center,
                    outer sep=0pt},
startstop/.style = {base, rounded corners, fill=blue!30},
  process/.style = {base, fill=orange!30},
 decision/.style = {base, diamond, aspect=1.3, fill=green!30},
       io/.style = {base, trapezium, trapezium stretches body,
                    trapezium left angle=70, trapezium right angle=110,
                    fill=red!30,
                    text width =\pgfkeysvalueof{/pgf/minimum width} - 2*\pgfkeysvalueof{/pgf/inner xsep}
                    },
     loop/.style = {base, rectangle split, rectangle split parts=2,
                    fill=gray!50},
    arrow/.style = {thick,-Triangle},
% suspend
suspend join/.code={\def\tikz@after@path{}}
                            }
        }% end of tikzset
 \makeatother

\begin{document}
    \textbf{Задача 1.}  \\
    Схема алгоритма:    \\
    \begin{center}
    \begin{tikzpicture}[FlowChart,
base/.append style = {on chain, join=by arrow},
    node distance = 5mm and 7mm,
      start chain = A going below
                        ]
% nodes in chain
\node (start)   [startstop] {Начало};
\node (input)   [io]        {Ввод n};
\node (ds1)     [decision]  {n = 0?};
\node (while)   [loop,
                 suspend join]  {\nodepart{one} While n > 0
                                 \nodepart{two} \begin{tabular}{cc}
                                                     n = n //10     \\
                                                     pow = pow +1   \\
                                                \end{tabular}
                                };
\node (output)  [io]        {Вывод pow};
\node (stop)    [startstop] {Конец программы};
% right branch
\node (y-case) [process,right=of ds1,
                suspend join]   {pow = 1};
%
\draw[arrow]    (ds1) to ["Yes"] (y-case);
\draw[arrow]    (y-case) |- (while);
\draw[arrow]    (ds1.west) to ["No" ']  ++ (-1,0) |- (while); % new
        \end{tikzpicture}
    \end{center}
\end{document}

Note: In above MWE are in comparison to yours changed the following:

• for the picture elements styles is used tikset instead of deprecated tikzstyle
• fo positioning of nodes is used syntax defined in positioning library (observe right=of ds1 instead of right of=ds1)
• nodes are organised in chain, which simplify code and make it shorter and more clear
• vertical connection lines are drawn by join macro defined in the chains macro
• join line between last node in the main branch and node right of decision node is interrupted by style code suspend join