《C++游戏编程入门》第1章 类型、变量与标准I/O: Lost Fortune
- 1.1.1 使用C++编写游戏
- 1.1.2 生成可执行文件
- 1.1.3 错误处理
- 1.2 第一个C++程序
- 01.game_over.cpp
- 01.game_over2.cpp
- 01.game_over3.cpp
- 1.4 使用算术运算符
- 01.expensive_calculator.cpp
- 1.5 声明和初始化变量
- 01.game_stats.cpp
- 1.6 使用变量进行算术运算
- 01.game_stats2.cpp
- 1.7 使用常量
- 01.game_stats3.cpp
- 1.8 Lost Fortune
- 01.lost_fortune.cpp
1.1.1 使用C++编写游戏
原因:
一、高速。高性能。
二、灵活。包括面向对象编程的多范型语言。
三、良好支持。大量资源库可使用,图像API、2D、3D、物理以及声音引擎。
1.1.2 生成可执行文件
编辑器->源代码->编译器->目标代码->链接器->可执行文件
1.1.3 错误处理
类型:
一、编译错误。语法错误,应修复警告。
二、链接错误。无法找到外部引用,调整引用关系,重新编译/链接。
三、运行错误。非法操作,逻辑错误等。
1.2 第一个C++程序
01.game_over.cpp
// 预处理器指令以#符号开头
// 包含头文件
#include <iostream>int main() // 主函数
{// std名称空间//::作用域解析运算符// 所有语句以;结尾std::cout << "Game Over!" << std::endl; // 标准输出return 0; // 0表示程序正常结束
}// 注释
/*
注释
注释
*/// 空白字符(空格、制表符、换行符)用于分隔代码块,会被编译器忽略
01.game_over2.cpp
#include <iostream>
using namespace std;//使用using指令int main()
{cout << "Game Over!" << endl;return 0;
}
01.game_over3.cpp
#include <iostream>
using std::cout;//使用using声明
using std::endl;int main()
{cout << "Game Over!" << endl;return 0;
}
1.4 使用算术运算符
01.expensive_calculator.cpp
#include <iostream>
using namespace std;int main()
{
//加法、加法与乘法cout << "7 + 3 = " << 7 + 3 << endl;cout << "7 - 3 = " << 7 - 3 << endl;cout << "7 * 3 = " << 7 * 3 << endl;cout << "7 / 3 = " << 7 / 3 << endl;//整数除法取整cout << "7.0 / 3.0 = " << 7.0 / 3.0 << endl;//除法,至少一个浮点数,保留小数位cout << "7 % 3 = " << 7 % 3 << endl;//余数cout << "7 + 3 * 5 = " << 7 + 3 * 5 << endl;cout << "(7 + 3) * 5 = " << (7 + 3) * 5 << endl;//运算符优先级return 0;
}
1.5 声明和初始化变量
01.game_stats.cpp
#include <iostream>
using namespace std;int main()
{int score; // 变量声明double distance;char playAgain;bool shieldsUp;short lives, aliensKilled; // 变量声明score = 0;distance = 1200.76;playAgain = 'y';shieldsUp = true;lives = 3;aliensKilled = 10; // 变量赋值double engineTemp = 6572.89; // 变量初始化cout << "\nscore: " << score << endl; // 显示变量值cout << "distance: " << distance << endl;cout << "playAgain: " << playAgain << endl;// skipping shieldsUp since you don't generally print Boolean valuescout << "lives: " << lives << endl;cout << "aliensKilled: " << aliensKilled << endl;cout << "engineTemp: " << engineTemp << endl;int fuel;cout << "\nHow much fuel? ";cin >> fuel; // 获取用户输入cout << "fuel: " << fuel << endl;typedef unsigned short int ushort; // 定义新变量名ushort bonus = 10;cout << "\nbonus: " << bonus << endl;return 0;
}// 基本类型
// bool, char, int, float, double// 类型修饰符
// short, long, signed, unsigned// 变量命名
// 字母,数字,下划线(非数字开头,非关键字)
// 命名准则:
// 描述性名称、前后一致、语言传统、短变量名// 根据数据使用范围选择数据类型
1.6 使用变量进行算术运算
01.game_stats2.cpp
#include <iostream>
using namespace std;int main()
{unsigned int score = 5000;cout << "score: " << score << endl;// altering the value of a variablescore = score + 100; // 修改变量值cout << "score: " << score << endl;// combined assignment operatorscore += 100; // 使用组合赋值运算符(+=,-=,*=,/=,%=)cout << "score: " << score << endl;// increment operatorsint lives = 3;++lives; // 前置递增运算符,--livescout << "lives: " << lives << endl;lives = 3;lives++; // 后置递增运算符,lives--cout << "lives: " << lives << endl;lives = 3;int bonus = ++lives * 10;cout << "lives, bonus = " << lives << ", " << bonus << endl;lives = 3;bonus = lives++ * 10;cout << "lives, bonus = " << lives << ", " << bonus << endl;// integer wrap aroundscore = 4294967295;cout << "\nscore: " << score << endl;++score; // 溢出,变为0cout << "score: " << score << endl;return 0;
}
1.7 使用常量
01.game_stats3.cpp
#include <iostream>
using namespace std;int main()
{const int ALIEN_POINTS = 150; // 常量,经过命名的无法修改的值int aliensKilled = 10;int score = aliensKilled * ALIEN_POINTS;cout << "score: " << score << endl;enum difficulty // 枚举类型{NOVICE,EASY,NORMAL,HARD,UNBEATABLE};difficulty myDifficulty = EASY;enum shipCost{FIGHTER_COST = 25,BOMBER_COST,CRUISER_COST = 50};shipCost myShipCost = BOMBER_COST;cout << "\nTo upgrade my ship to a Cruiser will cost "<< (CRUISER_COST - myShipCost) << " Resource Points.\n";return 0;
}
1.8 Lost Fortune
01.lost_fortune.cpp
#include <iostream>
#include <string>using std::cin;
using std::cout;
using std::endl;
using std::string;int main()
{const int GOLD_PIECES = 900;int adventurers, killed, survivors;string leader;// get the informationcout << "Welcome to Lost Fortune\n\n";cout << "Please enter the following for your personalized adventure\n";cout << "Enter a number: ";cin >> adventurers;cout << "Enter a number, smaller than the first: ";cin >> killed;survivors = adventurers - killed;cout << "Enter your last name: ";cin >> leader;// tell the storycout << "\nA brave group of " << adventurers << " set out on a quest ";cout << "-- in search of the lost treasure of the Ancient Dwarves. ";cout << "The group was led by that legendary rogue, " << leader << ".\n";cout << "\nAlong the way, a band of marauding ogres ambushed the party. ";cout << "All fought bravely under the command of " << leader;cout << ", and the ogres were defeated, but at a cost. ";cout << "Of the adventurers, " << killed << " were vanquished, ";cout << "leaving just " << survivors << " in the group.\n";cout << "\nThe party was about to give up all hope. ";cout << "But while laying the deceased to rest, ";cout << "they stumbled upon the buried fortune. ";cout << "So the adventurers split " << GOLD_PIECES << " gold pieces.";cout << leader << " held on to the extra " << (GOLD_PIECES % survivors);cout << " pieces to keep things fair of course.\n";return 0;
}