#108 named_scope

The named_scope method in Rails 2.1 makes performing finds on models very elegant and convenient. See how in this episode.
# models/product.rb
class Product < ActiveRecord::Base
belongs_to :category
named_scope :cheap, :conditions => { :price => 0..5 }
named_scope :recent, lambda { |*args| {:conditions => ["released_at > ?", (args.first || 2.weeks.ago)]} }
named_scope :visible, :include => :category, :conditions => { 'categories.hidden' => false }
end
g++ snake.cpp -o snake -lncurses snake.cpp:7:0: warning: "KEY_UP" redefined [enabled by default] #define KEY_UP 65 ^ In file included from snake.cpp:1:0: /usr/include/curses.h:1410:0: note: this is the location of the previous definition #define KEY_UP 0403 /* up-arrow key */ ^ snake.cpp:8:0: warning: "KEY_DOWN" redefined [enabled by default] #define KEY_DOWN 66 ^ In file included from snake.cpp:1:0: /usr/include/curses.h:1409:0: note: this is the location of the previous definition #define KEY_DOWN 0402 /* down-arrow key */ ^ snake.cpp:9:0: warning: "KEY_RIGHT" redefined [enabled by default] #define KEY_RIGHT 67 ^ In file included from snake.cpp:1:0: /usr/include/curses.h:1412:0: note: this is the location of the previous definition #define KEY_RIGHT 0405 /* right-arrow key */ ^ snake.cpp:10:0: warning: "KEY_LEFT" redefined [enabled by default] #define KEY_LEFT 68 ^ In file included from snake.cpp:1:0: /usr/include/curses.h:1411:0: note: this is the location of the previous definition #define KEY_LEFT 0404 /* left-arrow key */ ^ snake.cpp: In member function ‘void SnakeGame::generate_food()’: snake.cpp:25:23: error: ISO C++ forbids declaration of ‘p’ with no type [-fpermissive] for(auto& p : snake) ^ snake.cpp:25:27: error: range-based ‘for’ loops are not allowed in C++98 mode for(auto& p : snake) ^ snake.cpp:26:22: error: request for member ‘x’ in ‘p’, which is of non-class type ‘int’ if(p.x == food.x && p.y == food.y) continue; ^ snake.cpp:26:39: error: request for member ‘y’ in ‘p’, which is of non-class type ‘int’ if(p.x == food.x && p.y == food.y) continue; ^ snake.cpp: In constructor ‘SnakeGame::SnakeGame()’: snake.cpp:33:20: error: ‘nullptr’ was not declared in this scope srand(time(nullptr)); ^ snake.cpp:34:24: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11 [enabled by default] snake.push_back({LINES/2, COLS/2}); ^ snake.cpp:34:42: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11 [enabled by default] snake.push_back({LINES/2, COLS/2}); ^ snake.cpp: In member function ‘void SnakeGame::update()’: snake.cpp:69:19: error: ISO C++ forbids declaration of ‘p’ with no type [-fpermissive] for(auto& p : snake) ^ snake.cpp:69:23: error: range-based ‘for’ loops are not allowed in C++98 mode for(auto& p : snake) ^ snake.cpp:70:18: error: request for member ‘x’ in ‘p’, which is of non-class type ‘int’ if(p.x == head.x && p.y == head.y) { ^ snake.cpp:70:35: error: request for member ‘y’ in ‘p’, which is of non-class type ‘int’ if(p.x == head.x && p.y == head.y) { ^ snake.cpp: In member function ‘void SnakeGame::draw()’: snake.cpp:93:19: error: ISO C++ forbids declaration of ‘p’ with no type [-fpermissive] for(auto& p : snake) ^ snake.cpp:93:23: error: range-based ‘for’ loops are not allowed in C++98 mode for(auto& p : snake) ^ In file included from snake.cpp:1:0: snake.cpp:94:23: error: request for member ‘x’ in ‘p’, which is of non-class type ‘int’ mvaddch(p.x, p.y, &#39;*&#39;); ^ snake.cpp:94:28: error: request for member ‘y’ in ‘p’, which is of non-class type ‘int’ mvaddch(p.x, p.y, &#39;*&#39;); ^ snake.cpp: In function ‘int main()’: snake.cpp:124:49: error: ‘class SnakeGame’ has no member named ‘get_score’ printf("Game Over! Final Score: %d\n", game.get_score()); ^ [root@localhost ~]#
03-25
标题基于SpringBoot+Vue的社区便民服务平台研究AI更换标题第1章引言介绍社区便民服务平台的研究背景、意义,以及基于SpringBoot+Vue技术的研究现状和创新点。1.1研究背景与意义分析社区便民服务的重要性,以及SpringBoot+Vue技术在平台建设中的优势。1.2国内外研究现状概述国内外在社区便民服务平台方面的发展现状。1.3研究方法与创新点阐述本文采用的研究方法和在SpringBoot+Vue技术应用上的创新之处。第2章相关理论介绍SpringBoot和Vue的相关理论基础,以及它们在社区便民服务平台中的应用。2.1SpringBoot技术概述解释SpringBoot的基本概念、特点及其在便民服务平台中的应用价值。2.2Vue技术概述阐述Vue的核心思想、技术特性及其在前端界面开发中的优势。2.3SpringBoot与Vue的整合应用探讨SpringBoot与Vue如何有效整合,以提升社区便民服务平台的性能。第3章平台需求分析与设计分析社区便民服务平台的需求,并基于SpringBoot+Vue技术进行平台设计。3.1需求分析明确平台需满足的功能需求和性能需求。3.2架构设计设计平台的整体架构,包括前后端分离、模块化设计等思想。3.3数据库设计根据平台需求设计合理的数据库结构,包括数据表、字段等。第4章平台实现与关键技术详细阐述基于SpringBoot+Vue的社区便民服务平台的实现过程及关键技术。4.1后端服务实现使用SpringBoot实现后端服务,包括用户管理、服务管理等核心功能。4.2前端界面实现采用Vue技术实现前端界面,提供友好的用户交互体验。4.3前后端交互技术探讨前后端数据交互的方式,如RESTful API、WebSocket等。第5章平台测试与优化对实现的社区便民服务平台进行全面测试,并针对问题进行优化。5.1测试环境与工具介绍测试
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