《C++游戏编程入门》第3章 for循环、字符串与数组: World Jumble

3.1 使用for循环

03.counter.cpp

#include <iostream>
using namespace std;

int main()
{
    cout << "Counting forward:\n";
    for (int i = 0; i < 10; ++i)
    {
        cout << i << " ";
    }

    cout << "\n\nCounting backward:\n";
    for (int i = 9; i >= 0; --i)
    {
        cout << i << " ";
    }

    cout << "\n\nCounting by fives:\n";
    for (int i = 0; i <= 50; i += 5)
    {
        cout << i << " ";
    }

    cout << "\n\nCounting with null statements:\n";
    int count = 0;
    for (; count < 10;)
    {
        cout << count << " ";
        ++count;
    }

    cout << "\n\nCounting with nested for loops:\n";
    const int ROWS = 5;
    const int COLUMNS = 3;
    for (int i = 0; i < ROWS; ++i)
    {
        for (int j = 0; j < COLUMNS; ++j)
        {
            cout << i << "," << j << "  ";
        }

        cout << endl;
    }

    return 0;
}

3.2 了解对象

类与对象，数据与函数封装。

3.3 使用string对象

03.string_tester.cpp

#include <iostream>
#include <string>
using namespace std;

int main()
{
    // 创建string对象
    string word1 = "Game";
    string word2("Over");
    string word3(3, '!');

    string phrase = word1 + " " + word2 + word3; // string对象连接
    cout << "The phrase is: " << phrase << "\n\n";

    cout << "The phrase has " << phrase.size() << " characters in it.\n\n"; // size()成员函数

    cout << "The character at position 0 is: " << phrase[0] << "\n\n"; // 索引获取字符

    cout << "Changing the character at position 0.\n";
    phrase[0] = 'L'; // 索引字符赋值
    cout << "The phrase is now: " << phrase << "\n\n";

    for (unsigned int i = 0; i < phrase.size(); ++i) // 循环访问单个字符
    {
        cout << "Character at position " << i << " is: " << phrase[i] << endl;
    }

    cout << "\nThe sequence 'Over' begins at location ";
    cout << phrase.find("Over") << endl; // find()查找字符串

    if (phrase.find("eggplant") == string::npos) // 未找到
    {
        cout << "'eggplant' is not in the phrase.\n\n";
    }

    phrase.erase(4, 5); // 移除从位置4开始的长度为5个字符的子字符串
    cout << "The phrase is now: " << phrase << endl;

    phrase.erase(4);
    cout << "The phrase is now: " << phrase << endl;

    phrase.erase();
    cout << "The phrase is now: " << phrase << endl;

    if (phrase.empty())//是否空
    {
        cout << "\nThe phrase is no more.\n";
    }

    return 0;
}

3.4 使用数组

存储多个相同类型的元素。

03.heros_inventory.cpp

#include <iostream>
#include <string>
using namespace std;

int main()
{
    const int MAX_ITEMS = 10;
    string inventory[MAX_ITEMS];//创建数组

    int numItems = 0;//数组索引
    inventory[numItems++] = "sword";
    inventory[numItems++] = "armor";
    inventory[numItems++] = "shield";

    cout << "Your items:\n";
    for (int i = 0; i < numItems; ++i)
    {
        cout << inventory[i] << endl;
    }

    cout << "\nYou trade your sword for a battle axe.";
    inventory[0] = "battle axe";
    cout << "\nYour items:\n";
    for (int i = 0; i < numItems; ++i)
    {
        cout << inventory[i] << endl;
    }

    cout << "\nThe item name '" << inventory[0] << "' has ";
    cout << inventory[0].size() << " letters in it.\n";

    cout << "\nYou find a healing potion.";
    if (numItems < MAX_ITEMS)
    {
        inventory[numItems++] = "healing potion";
    }
    else
    {
        cout << "You have too many items and can't carry another.";
    }
    cout << "\nYour items:\n";
    for (int i = 0; i < numItems; ++i)
    {
        cout << inventory[i] << endl;
    }

    return 0;
}

3.6 多维数组

03.tic-tac-toe_board.cpp

#include <iostream>
using namespace std;

int main()
{
    const int ROWS = 3;
    const int COLUMNS = 3; // 创建多维数组
    char board[ROWS][COLUMNS] = {{'O', 'X', 'O'},
                                 {' ', 'X', 'X'},
                                 {'X', 'O', 'O'}};

    cout << "Here's the tic-tac-toe board:\n";
    for (int i = 0; i < ROWS; ++i)
    {
        for (int j = 0; j < COLUMNS; ++j)
        {
            cout << board[i][j]; // 多维数组索引
        }

        cout << endl;
    }

    cout << "\n'X' moves to the empty location.\n\n";
    board[1][0] = 'X';

    cout << "Now the tic-tac-toe board is:\n";
    for (int i = 0; i < ROWS; ++i)
    {
        for (int j = 0; j < COLUMNS; ++j)
        {
            cout << board[i][j];
        }

        cout << endl;
    }

    cout << "\n'X' wins!";

    return 0;
}

3.7 World Jumble程序

03.word_jumble.cpp

#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std;

int main()
{
    enum fields
    {
        WORD,
        HINT,
        NUM_FIELDS
    };
    const int NUM_WORDS = 5; // 单词列表以及提示
    const string WORDS[NUM_WORDS][NUM_FIELDS] =
        {
            {"wall", "Do you feel you're banging your head against something?"},
            {"glasses", "These might help you see the answer."},
            {"labored", "Going slowly, is it?"},
            {"persistent", "Keep at it."},
            {"jumble", "It's what the game is all about."}};

    // 随机选择单词
    srand(static_cast<unsigned int>(time(0)));
    int choice = (rand() % NUM_WORDS);
    string theWord = WORDS[choice][WORD]; // word to guess
    string theHint = WORDS[choice][HINT]; // hint for word

    // 单词乱序
    string jumble = theWord; // jumbled version of word
    int length = jumble.size();
    for (int i = 0; i < length; ++i)
    {
        int index1 = (rand() % length);
        int index2 = (rand() % length);
        char temp = jumble[index1];
        jumble[index1] = jumble[index2];
        jumble[index2] = temp;
    }

    // 欢迎界面
    cout << "\t\t\tWelcome to Word Jumble!\n\n";
    cout << "Unscramble the letters to make a word.\n";
    cout << "Enter 'hint' for a hint.\n";
    cout << "Enter 'quit' to quit the game.\n\n";
    cout << "The jumble is: " << jumble;

    string guess;
    cout << "\n\nYour guess: ";
    cin >> guess;

    // 游戏主循环
    while ((guess != theWord) && (guess != "quit"))
    {
        if (guess == "hint")
        {
            cout << theHint;
        }
        else
        {
            cout << "Sorry, that's not it.";
        }

        cout << "\n\nYour guess: ";
        cin >> guess;
    }

    // 游戏结束
    if (guess == theWord)
    {
        cout << "\nThat's it!  You guessed it!\n";
    }

    cout << "\nThanks for playing.\n";

    return 0;
}