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 guessstring theHint = WORDS[choice][HINT]; // hint for word// 单词乱序string jumble = theWord; // jumbled version of wordint 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;
}