TikZ 그래픽

\usepackage{tikz}

\begin{tikzpicture}
  % 선 그리기
  \draw (0,0) -- (3,0);              % 수평선
  \draw (0,0) -- (3,2);              % 대각선
  \draw[thick, red] (0,0) -- (0,3);  % 굵은 빨간 수직선

  % 사각형
  \draw (0,0) rectangle (3,2);
  \draw[blue, fill=blue!20] (4,0) rectangle (7,2);

  % 원
  \draw (1.5,4) circle (1);
  \fill[green!30] (5.5,4) circle (0.8);

  % 타원
  \draw (1.5,7) ellipse (1.5 and 0.8);

  % 호 (arc)
  \draw (5,7) arc (0:180:1);         % 시작각:끝각:반지름

  % 둥근 모서리 사각형
  \draw[rounded corners=5pt] (0,9) rectangle (3,10.5);
\end{tikzpicture}

\begin{tikzpicture}
  % 기본 노드
  \node at (0,0) {텍스트};
  \node[draw] at (3,0) {테두리 있는 노드};
  \node[draw, circle] at (6,0) {원형};

  % 노드 스타일
  \node[draw, rectangle, fill=yellow!30,
        minimum width=2cm, minimum height=1cm]
    at (0,-2) {스타일 적용};

  % 이름 있는 노드 (연결에 사용)
  \node[draw, circle] (A) at (0,-4) {A};
  \node[draw, circle] (B) at (3,-4) {B};
  \node[draw, circle] (C) at (6,-4) {C};

  % 노드 간 연결
  \draw[->] (A) -- (B);
  \draw[->, thick] (B) -- (C);
  \draw[->, dashed] (A) to[bend left=30] (C);

  % 연결선 위에 라벨
  \draw[->] (A) -- node[above] {5} (B);
  \draw[->] (B) -- node[below] {3} (C);
\end{tikzpicture}

\usetikzlibrary{shapes.geometric, arrows.meta, positioning}

\begin{tikzpicture}[
  startstop/.style={rectangle, rounded corners, draw, fill=red!30,
    minimum width=3cm, minimum height=1cm},
  process/.style={rectangle, draw, fill=blue!20,
    minimum width=3cm, minimum height=1cm},
  decision/.style={diamond, draw, fill=green!20,
    minimum width=2.5cm, minimum height=1cm, aspect=2},
  arrow/.style={thick, -Stealth},
  node distance=1.5cm
]

  \node[startstop] (start) {시작};
  \node[process, below of=start] (input) {데이터 입력};
  \node[decision, below of=input] (decide) {유효한가?};
  \node[process, below of=decide, yshift=-0.5cm] (process) {데이터 처리};
  \node[process, right of=decide, xshift=3cm] (error) {오류 처리};
  \node[startstop, below of=process] (stop) {종료};

  \draw[arrow] (start) -- (input);
  \draw[arrow] (input) -- (decide);
  \draw[arrow] (decide) -- node[left] {예} (process);
  \draw[arrow] (decide) -- node[above] {아니오} (error);
  \draw[arrow] (error) |- (input);
  \draw[arrow] (process) -- (stop);

\end{tikzpicture}

\begin{tikzpicture}
  % 절대 좌표
  \draw (0,0) -- (2,1) -- (4,0);

  % 상대 좌표 (++ : 이전 점 기준)
  \draw (0,-2) -- ++(2,1) -- ++(2,-1);

  % 그리드 (격자)
  \draw[step=0.5, gray!30, very thin] (0,-5) grid (6,-3);
  \draw[thick, ->] (0,-5) -- (6.3,-5) node[right] {$x$};
  \draw[thick, ->] (0,-5) -- (0,-2.7) node[above] {$y$};

  % 함수 그래프 (plot)
  \draw[domain=0:6, smooth, blue, thick]
    plot (\x, {-4 + sin(\x * 60)});

  % 데이터 포인트 표시
  \foreach \x/\y in {1/-3.5, 2/-4.2, 3/-3.1, 4/-4.5, 5/-3.8} {
    \fill[red] (\x, \y) circle (2pt);
  }

  % 화살표 스타일
  \draw[->, >=latex] (0,-7) -- (2,-7);        % LaTeX 화살표
  \draw[->, >=stealth] (3,-7) -- (5,-7);      % Stealth 화살표
  \draw[<->, >=stealth] (0,-8) -- (5,-8);     % 양방향

  % 패턴 채우기
  \fill[pattern=north east lines] (0,-10) rectangle (2,-9);
  \fill[pattern=dots] (3,-10) rectangle (5,-9);
\end{tikzpicture}