# GESP等级：二级 | GESP Python 二级考点 """ 流程图小画家演示程序 面向7-10岁少儿编程教学 用 turtle 画出 "判断奇偶数" 的完整流程图 """ import turtle # ============================================================ # 初始化画布和画笔 # ============================================================ t = turtle.Turtle() t.speed(3) t.pensize(2) turtle.title("流程图小画家 - 判断奇偶数") turtle.bgcolor("white") # 颜色定义 COLOR_START = "green" # 开始/结束 COLOR_PROCESS = "blue" # 处理框 COLOR_DECISION = "orange" # 判断框 COLOR_ARROW = "black" # 箭头 COLOR_TEXT = "black" # 文字 # ============================================================ # 工具函数 # ============================================================ def go_to(x, y): """移动到指定坐标（不画线）""" t.penup() t.goto(x, y) t.pendown() def draw_arrow(x1, y1, x2, y2, label=""): """从 (x1,y1) 画箭头到 (x2,y2)，可加标签""" t.penup() t.goto(x1, y1) t.pendown() t.pensize(2) t.pencolor(COLOR_ARROW) # 计算角度 import math dx = x2 - x1 dy = y2 - y1 angle = math.degrees(math.atan2(dy, dx)) # 画线 t.setheading(t.towards(x2, y2)) t.forward(math.sqrt(dx*dx + dy*dy)) # 画箭头头部 t.penup() t.goto(x2, y2) t.pendown() t.setheading(angle) t.left(150) t.forward(10) t.penup() t.goto(x2, y2) t.pendown() t.setheading(angle) t.right(150) t.forward(10) # 画标签 if label: t.penup() label_x = (x1 + x2) / 2 label_y = (y1 + y2) / 2 t.goto(label_x, label_y + 12) t.pendown() t.pencolor("red") t.write(label, align="center", font=("SimHei", 10, "normal")) t.pencolor(COLOR_ARROW) def draw_ellipse(x, y, w, h, text, color=COLOR_START): """画椭圆（起止框）""" go_to(x, y) t.pensize(2) t.pencolor(color) t.fillcolor("light" + color if color == "green" else "lightcoral") t.fillcolor("#E8F5E9" if color == COLOR_START else "#FFF3E0") # 画椭圆（使用圆弧组合） t.penup() t.goto(x - w//2, y) t.pendown() t.fillcolor("#E8F5E9") t.begin_fill() for i in range(2): t.circle(h//2, 90) t.circle(w//2 - h//2, 90) t.end_fill() # 写文字 t.penup() t.goto(x, y - 8) t.pendown() t.pencolor(COLOR_TEXT) t.write(text, align="center", font=("SimHei", 12, "bold")) def draw_rect(x, y, w, h, text, color=COLOR_PROCESS): """画矩形（处理框）""" go_to(x - w//2, y - h//2) t.pensize(2) t.pencolor(color) t.fillcolor("#E3F2FD") t.begin_fill() for _ in range(2): t.forward(w) t.left(90) t.forward(h) t.left(90) t.end_fill() # 写文字 t.penup() t.goto(x, y - 8) t.pendown() t.pencolor(COLOR_TEXT) t.write(text, align="center", font=("SimHei", 12, "bold")) def draw_diamond(x, y, size, text, color=COLOR_DECISION): """画菱形（判断框）""" go_to(x, y + size) t.pensize(2) t.pencolor(color) t.fillcolor("#FFF3E0") t.begin_fill() t.goto(x + size, y) t.goto(x, y - size) t.goto(x - size, y) t.goto(x, y + size) t.end_fill() # 写文字（分两行） t.penup() t.goto(x, y - 14) t.pendown() t.pencolor(COLOR_TEXT) t.write(text, align="center", font=("SimHei", 11, "bold")) def draw_title(): """画标题""" go_to(0, 250) t.pencolor("purple") t.write("流程图小画家 —— 判断奇偶数", align="center", font=("SimHei", 18, "bold")) # ============================================================ # 主程序：画判断奇偶数的完整流程图 # ============================================================ def main(): t.speed(5) turtle.tracer(False) # 先关动画，画完再显示 draw_title() # ============ 第1层：开始 ============ y_start = 190 draw_ellipse(0, y_start, 120, 50, "开始", COLOR_START) # 箭头：开始 → 输入数字 draw_arrow(0, y_start - 25, 0, y_start - 75) # ============ 第2层：输入数字 ============ y_input = y_start - 100 draw_rect(0, y_input, 180, 50, "输入数字 n", COLOR_PROCESS) # 箭头：输入 → 判断 draw_arrow(0, y_input - 25, 0, y_input - 75) # ============ 第3层：判断条件 ============ y_decision = y_input - 100 draw_diamond(0, y_decision, 60, "n % 2 == 0 ?", COLOR_DECISION) # 箭头：判断 → 是（左分支） draw_arrow(-60, y_decision - 15, -120, y_decision - 75, "是") # 箭头：判断 → 否（右分支） draw_arrow(60, y_decision - 15, 120, y_decision - 75, "否") # ============ 第4层左：输出偶数 ============ y_left = y_decision - 100 draw_rect(-120, y_left, 180, 50, "输出 '是偶数'", COLOR_PROCESS) # 箭头：左输出 → 结束 draw_arrow(-120, y_left - 25, -60, y_left - 75) # ============ 第4层右：输出奇数 ============ draw_rect(120, y_left, 180, 50, "输出 '是奇数'", COLOR_PROCESS) # 箭头：右输出 → 结束 draw_arrow(120, y_left - 25, 60, y_left - 75) # ============ 第5层：结束 ============ y_end = y_left - 100 draw_ellipse(0, y_end, 120, 50, "结束", COLOR_START) # 汇聚线：左边和右边汇聚到结束 # 左边已经画了到 (-60, y_left-75)，需要到 (0, y_end) draw_arrow(-60, y_left - 25, 0, y_end + 25) draw_arrow(60, y_left - 25, 0, y_end + 25) # ============ 图例 ============ y_legend = y_end - 80 go_to(-200, y_legend) t.pencolor("green") t.write("椭圆 = 开始/结束（起止框）", font=("SimHei", 10, "normal")) go_to(-200, y_legend - 22) t.pencolor("blue") t.write("矩形 = 做事（处理框）", font=("SimHei", 10, "normal")) go_to(-200, y_legend - 44) t.pencolor("orange") t.write("菱形 = 选择（判断框）", font=("SimHei", 10, "normal")) go_to(-200, y_legend - 66) t.pencolor("black") t.write("箭头 = 方向（流程线）", font=("SimHei", 10, "normal")) # ============ 对应的Python代码 ============ y_code = y_legend - 100 go_to(-200, y_code) t.pencolor("purple") t.write("对应的Python代码：", font=("SimHei", 12, "bold")) code_lines = [ "n = int(input('输入数字：'))", "if n % 2 == 0:", " print('是偶数')", "else:", " print('是奇数')", ] for i, line in enumerate(code_lines): go_to(-200, y_code - 25 * (i + 1)) t.pencolor("darkblue") t.write(line, font=("Courier New", 10, "normal")) # ============ 三种结构标注 ============ go_to(150, y_start + 20) t.pencolor("red") t.write("→顺序结构", font=("SimHei", 11, "bold")) go_to(150, y_decision + 20) t.pencolor("red") t.write("→选择结构", font=("SimHei", 11, "bold")) # 刷新显示 t.hideturtle() turtle.tracer(True) turtle.done() # ============================================================ # 启动程序 # ============================================================ if __name__ == "__main__": print("=" * 40) print(" 流程图小画家 —— turtle画流程图") print(" 主题：判断一个数是奇数还是偶数") print("=" * 40) print() print("📐 图例说明：") print(" 椭圆 🟢 = 开始 / 结束（起止框）") print(" 矩形 🔵 = 处理（处理框）") print(" 菱形 🟠 = 判断（判断框）") print(" 箭头 ⬆⬇ = 流程方向（流程线）") print() print("📝 对应的 Python 代码：") print(" n = int(input('输入数字：'))") print(" if n % 2 == 0:") print(" print('是偶数')") print(" else:") print(" print('是奇数')") print() print("🖥️ 流程图将显示在窗口中……") main()