提交第一章

代码 + txt笔记

chapt1/1_01.cpp

@@ -0,0 +1,14 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+int main()
+{
+    string user_name;
+
+    cout << "Please enter your first name: ";
+    cin >> user_name;
+    cout << "\nHello, " << "Hello,  " << user_name << " ... and goodbye!\n";
+
+    return 0;
+}

chapt1/1_02.cpp

@@ -0,0 +1,97 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+int main(void)
+{
+    string user_name;
+    int user_guess;
+    int num_tries;              // 总的猜测数
+    int num_right;              // 总的正确数
+    double user_score = 0.0;
+    char user_rsp;
+    char try_again;
+    bool next_seq = true;       // 显示下一组数列 
+    bool go_for_it = true;      // 用户想继续猜一次
+    bool got_it = false;         // 用户是否猜对 
+    const int max_tries = 3;
+
+    const int seq_size = 18;
+    const int max_seq = 6;
+    int elem_seq[seq_size] = {
+        1, 2, 3,    // Fibonacci
+        3, 4, 7,    // Lucas
+        2, 5, 12,   // Pell
+        3, 6, 10,   // Triangular
+        4, 9, 16,   // Square
+        5, 12, 22   // Pentagonal
+    };
+    string seq_names[max_seq] = {
+        "Fibonacci",
+        "Lucas",
+        "Pell",
+        "Triangular",
+        "Square",
+        "Pentagonal"
+    };
+    int cur_index = 0;
+
+
+    // 用户想要继续猜某个数列
+    while (next_seq == true && cur_index < seq_size)
+    {
+        // 显示数列的前两个数字
+        std::cout << "The first 2 elements of the sequence are: "
+                    << elem_seq[cur_index] << ", " << elem_seq[cur_index+1] << endl;
+        std::cout << "What is the next element?";
+        int tries_cnt = 0;
+        next_seq = true;
+        go_for_it = true;
+        got_it = false;
+        // 用户所猜不正确 && 用户想要再猜一次
+        while(!got_it && go_for_it && (++tries_cnt <= max_tries))
+        {
+            std::cin >> user_guess;
+            ++num_tries;
+            //  如果答案正确
+            if(user_guess == elem_seq[cur_index+2])
+            {
+                ++num_right;
+                std::cout << "Very good, yes, " << elem_seq[cur_index+2]
+                            << " is the next element in the "
+                            << seq_names[cur_index/3] << "  sequence." << endl;
+                got_it = true;
+            }else{
+            // 如果答案错误
+                switch (tries_cnt)
+                {
+                case 1:
+                    std::cout << "Oops, Nice guess but not quite it." << endl;
+                    break;
+                case 2:
+                    std::cout << "Sorry, Wrong a second time!" << endl;
+                    break;
+                case 3:
+                    std::cout << "Ah, this is harder than it looks, isn't it?" << endl;
+                    break;
+                default:
+                    std::cout << "It must be getting pretty frustrating by now!!!" << endl;
+                    break;
+                }
+
+                std::cout << "do you want to continue?(y/n):" << endl;
+                std::cin >> user_rsp;
+                if(user_rsp == 'N' || user_rsp == 'n')
+                    go_for_it = false;
+            } 
+        } // 内层while结束
+        std::cout  << "Want to try another sequence? (y/n)?" << endl;
+        std::cin >> try_again;
+        if(try_again == 'N' || try_again == 'n')
+            next_seq = false;
+        else
+            cur_index += 3;
+    }   // 外层while结束
+
+    return 0;
+}

chapt1/1_03.cpp

@@ -0,0 +1,20 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+int main()
+{
+    const int seq_size = 18;
+    vector<int> pell_seq(seq_size);
+    pell_seq[0] = 1;
+    pell_seq[1] = 2;
+    for (int index = 2; index < seq_size; index++)
+        pell_seq[index] = 2 * pell_seq[index-1] + pell_seq[index-2];
+
+    cout << "The first " << pell_seq.size() << " elements of the Pell series:" << endl;
+    for (int index = 0; index < seq_size; index++)
+        cout << pell_seq[index] << " ";
+    cout << endl;
+
+    return 0;
+}

chapt1/1_04.cpp

@@ -0,0 +1,112 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <cstdlib>
+#include <ctime>
+using namespace std;
+
+int main(void)
+{
+    string user_name;
+    int user_guess;
+    int num_tries;              // 总的猜测数
+    int num_right;              // 总的正确数
+    double user_score = 0.0;
+    char user_rsp;
+    char try_again;
+    bool next_seq = true;       // 显示下一组数列 
+    bool go_for_it = true;      // 用户想继续猜一次
+    bool got_it = false;         // 用户是否猜对 
+    const int max_tries = 3;
+
+    const int seq_size = 18;
+    int elem_seq[seq_size] = {
+        1, 2, 3,    // Fibonacci
+        3, 4, 7,    // Lucas
+        2, 5, 12,   // Pell
+        3, 6, 10,   // Triangular
+        4, 9, 16,   // Square
+        5, 12, 22   // Pentagonal
+    };
+    vector<int> fibonacci(elem_seq, elem_seq+3);
+    vector<int> Lucas(elem_seq+3, elem_seq+6);
+    vector<int> Pell(elem_seq+6, elem_seq+9);
+    vector<int> Triangular(elem_seq+9, elem_seq+12);
+    vector<int> Square(elem_seq+12, elem_seq+15);
+    vector<int> Pentagonal(elem_seq+15, elem_seq+18);
+
+    const int max_seq = 6;
+    string seq_names[max_seq] = {
+        "Fibonacci",
+        "Lucas",
+        "Pell",
+        "Triangular",
+        "Square",
+        "Pentagonal"
+    };
+    vector<int> * seq_addrs[max_seq] = {
+        &fibonacci, &Lucas, &Pell,
+        &Triangular, &Square, &Pentagonal
+    };
+
+    vector<int> *current_vec = 0;
+    int seq_index;
+    srand(time(NULL));
+
+    // 用户想要继续猜某个数列
+    while (next_seq == true)
+    {
+        seq_index = rand() % max_seq;
+        current_vec = seq_addrs[seq_index];
+        std::cout << "The first 2 elements of the sequence are: "
+                    << (*current_vec)[0] << ", " <<  (*current_vec)[1] << endl;
+        std::cout << "What is the next element?";
+        int tries_cnt = 0;
+        next_seq = true;
+        go_for_it = true;
+        got_it = false;
+        // 用户所猜不正确 && 用户想要再猜一次
+        while(!got_it && go_for_it && (++tries_cnt <= max_tries))
+        {
+            std::cin >> user_guess;
+            ++num_tries;
+            //  如果答案正确
+            if(user_guess ==  (*current_vec)[2])
+            {
+                ++num_right;
+                std::cout << "Very good, yes, " <<   (*current_vec)[2]
+                            << " is the next element in the "
+                            << seq_names[seq_index] << "  sequence." << endl;
+                got_it = true;
+            }else{
+            // 如果答案错误
+                switch (tries_cnt)
+                {
+                case 1:
+                    std::cout << "Oops, Nice guess but not quite it." << endl;
+                    break;
+                case 2:
+                    std::cout << "Sorry, Wrong a second time!" << endl;
+                    break;
+                case 3:
+                    std::cout << "Ah, this is harder than it looks, isn't it?" << endl;
+                    break;
+                default:
+                    std::cout << "It must be getting pretty frustrating by now!!!" << endl;
+                    break;
+                }
+
+                std::cout << "do you want to continue?(y/n):" << endl;
+                std::cin >> user_rsp;
+                if(user_rsp == 'N' || user_rsp == 'n')
+                    go_for_it = false;
+            } 
+        } // 内层while结束
+        std::cout  << "Want to try another sequence? (y/n)?" << endl;
+        std::cin >> try_again;
+        if(try_again == 'N' || try_again == 'n')
+            next_seq = false;
+    }   // 外层while结束
+
+    return 0;
+}

chapt1/1_05.cpp

@@ -0,0 +1,28 @@
+#include <iostream>
+#include <fstream>
+using namespace std;
+
+int main()
+{
+    string name;
+    int num_tries;
+    int num_rights;
+    ofstream outfile("1_05.txt", ios_base::app);
+
+    cout << "Enter your name: ";
+    cin >> name;
+    cout << "Enter your num_tries, num_rights: ";
+    cin >> num_tries >>num_rights;
+    if (!outfile)
+    {
+        cerr << "Oops, unable to save session data!" << endl;
+    }else
+    {
+        outfile << name << ' ' 
+                << num_tries << ' ' 
+                << num_rights << ' ' << endl;
+    }
+
+
+    return 0;
+}

chapt1/1_06.cpp

@@ -0,0 +1,25 @@
+#include <iostream>
+#include <fstream>
+using namespace std;
+
+int main()
+{
+    string name;
+    int num_tries;
+    int num_rights;
+    ifstream infile("1_05.txt");
+
+    if (!infile)
+    {
+        cerr << "Oops, unable to open file!" << endl;
+    }else
+    {
+        infile >> name >> num_tries >> num_rights;
+        cout << "name: " << name << endl;
+        cout << "tot: " << num_tries << endl;
+        cout << "right: " << num_rights << endl;
+    }
+
+
+    return 0;
+}

chapt1/1_07.cpp

@@ -0,0 +1,34 @@
+#include <iostream>
+#include <fstream>
+using namespace std;
+
+int main()
+{
+    string name;
+    int num_tries;
+    int num_rights;
+
+    fstream iofile("data.txt", ios_base::in | ios_base::app);
+    if(!iofile)
+    {
+        cerr << "Oops, unable to open file!" << endl;
+
+    }else
+    {
+        iofile << "andy " << 10 << ' ' << 7 << endl;
+        cout << "______________________" << endl;
+        string usr_name;
+        int num_tries = 0;
+        int num_rights = 0;
+
+        // 由于ios_base::app的原因，开始读取之前，请将文件重新定位到起始处
+        iofile.seekg(0);
+        iofile >> usr_name >> num_tries >> num_rights;
+        cout << "name: " << usr_name << endl;
+        cout << "tot: " << num_tries << endl;
+        cout << "right: " << num_rights << endl;
+    }
+
+
+    return 0;
+}