提交第四章书中源代码

source/chapter04/addpntrs.cpp

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+// addpntrs.cpp -- pointer addition
+#include <iostream>
+int main()
+{
+    using namespace std;
+    double wages[3] = {10000.0, 20000.0, 30000.0};
+    short stacks[3] = {3, 2, 1};
+
+// Here are two ways to get the address of an array
+    double * pw = wages;     // name of an array = address
+    short * ps = &stacks[0]; // or use address operator
+// with array element
+    cout << "pw = " << pw << ", *pw = " << *pw << endl;
+    pw = pw + 1;
+    cout << "add 1 to the pw pointer:\n";
+    cout << "pw = " << pw << ", *pw = " << *pw << "\n\n";
+
+    cout << "ps = " << ps << ", *ps = " << *ps << endl;
+    ps = ps + 1;
+    cout << "add 1 to the ps pointer:\n";
+    cout << "ps = " << ps << ", *ps = " << *ps << "\n\n";
+
+    cout << "access two elements with array notation\n";
+    cout << "stacks[0] = " << stacks[0] 
+         << ", stacks[1] = " << stacks[1] << endl;
+    cout << "access two elements with pointer notation\n";
+
+    cout << "*stacks = " << *stacks
+         << ", *(stacks + 1) =  " << *(stacks + 1) << endl;
+
+    cout << sizeof(wages) << " = size of wages array\n";
+    cout << sizeof(pw) << " = size of pw pointer\n";
+    // cin.get();
+    return 0; 
+}

source/chapter04/address.cpp

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+// address.cpp -- using the & operator to find addresses
+#include <iostream>
+int main()
+{
+    using namespace std;
+    int donuts = 6;
+    double cups = 4.5;
+
+    cout << "donuts value = " << donuts;
+    cout << " and donuts address = " << &donuts << endl;
+// NOTE: you may need to use unsigned (&donuts)
+// and unsigned (&cups)
+    cout << "cups value = " << cups;
+    cout << " and cups address = " << &cups << endl;
+    // cin.get();
+    return 0; 
+}

source/chapter04/arraynew.cpp

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+// arraynew.cpp -- using the new operator for arrays
+#include <iostream>
+int main()
+{
+    using namespace std;
+    double * p3 = new double [3]; // space for 3 doubles
+    p3[0] = 0.2;                  // treat p3 like an array name
+    p3[1] = 0.5;
+    p3[2] = 0.8;
+    cout << "p3[1] is " << p3[1] << ".\n";
+    p3 = p3 + 1;                  // increment the pointer
+    cout << "Now p3[0] is " << p3[0] << " and ";
+    cout << "p3[1] is " << p3[1] << ".\n";
+    p3 = p3 - 1;                  // point back to beginning
+    delete [] p3;                 // free the memory
+    // cin.get();
+    return 0; 
+}

source/chapter04/arrayone.cpp

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+// arrayone.cpp -- small arrays of integers
+#include <iostream>
+int main()
+{
+    using namespace std;
+    int yams[3];    // creates array with three elements
+    yams[0] = 7;    // assign value to first element
+    yams[1] = 8;
+    yams[2] = 6;
+
+    int yamcosts[3] = {20, 30, 5}; // create, initialize array
+
+    // NOTE: If your C++ compiler or translator can't initialize
+    // this array, use static int yamcosts[3] instead of
+    // int yamcosts[3]
+
+    cout << "Total yams = ";
+    cout << yams[0] + yams[1] + yams[2] << endl;
+    cout << "The package with " << yams[1] << " yams costs ";
+    cout << yamcosts[1] << " cents per yam.\n";
+    int total = yams[0] * yamcosts[0] + yams[1] * yamcosts[1];
+    total = total + yams[2] * yamcosts[2];
+    cout << "The total yam expense is " << total << " cents.\n";
+
+    cout << "\nSize of yams array = " << sizeof yams;
+    cout << " bytes.\n";
+    cout << "Size of one element = " << sizeof yams[0];
+    cout << " bytes.\n";
+
+    // cin.get();
+    return 0; 
+}

source/chapter04/arrstruct.cpp

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+// arrstruc.cpp -- an array of structures
+#include <iostream>
+struct inflatable
+{
+    char name[20];
+    float volume;
+    double price;
+};
+int main()
+{
+    using namespace std;
+    inflatable guests[2] =          // initializing an array of structs
+    {
+        {"Bambi", 0.5, 21.99},      // first structure in array
+        {"Godzilla", 2000, 565.99}  // next structure in array
+    };
+
+    cout << "The guests " << guests[0].name << " and " << guests[1].name
+         << "\nhave a combined volume of "
+         << guests[0].volume + guests[1].volume << " cubic feet.\n";
+    // cin.get();
+    return 0; 
+}

source/chapter04/assgn_st.cpp

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+// assgn_st.cpp -- assigning structures
+#include <iostream>
+struct inflatable
+{
+    char name[20];
+    float volume;
+    double price;
+};
+int main()
+{
+    using namespace std;
+    inflatable bouquet =
+    {
+        "sunflowers",
+        0.20,
+        12.49
+    };
+    inflatable choice;
+    cout << "bouquet: " << bouquet.name << " for $";
+    cout << bouquet.price << endl;
+
+    choice = bouquet;  // assign one structure to another
+    cout << "choice: " << choice.name << " for $";
+    cout << choice.price << endl;
+    // cin.get();
+    return 0; 
+}

source/chapter04/choices.cpp

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+// choices.cpp -- array variations
+#include <iostream>
+#include <vector>   // STL C++98
+#include <array>    // C++0x
+int main()
+{
+    using namespace std;
+// C, original C++
+    double a1[4] = {1.2, 2.4, 3.6, 4.8};
+// C++98 STL
+    vector<double> a2(4);   // create vector with 4 elements
+// no simple way to initialize in C98
+    a2[0] = 1.0/3.0;
+    a2[1] = 1.0/5.0;
+    a2[2] = 1.0/7.0;
+    a2[3] = 1.0/9.0;
+// C++0x -- create and initialize array object
+    array<double, 4> a3 = {3.14, 2.72, 1.62, 1.41};  
+    array<double, 4> a4;
+    a4 = a3;     // valid for array objects of same size
+// use array notation
+    cout << "a1[2]: " << a1[2] << " at " << &a1[2] << endl;
+    cout << "a2[2]: " << a2[2] << " at " << &a2[2] << endl;
+    cout << "a3[2]: " << a3[2] << " at " << &a3[2] << endl;
+    cout << "a4[2]: " << a4[2] << " at " << &a4[2] << endl;
+// misdeed
+    a1[-2] = 20.2;
+    cout << "a1[-2]: " << a1[-2] <<" at " << &a1[-2] << endl;
+    cout << "a3[2]: " << a3[2] << " at " << &a3[2] << endl;
+    cout << "a4[2]: " << a4[2] << " at " << &a4[2] << endl;
+    //  cin.get();
+    return 0;
+}

source/chapter04/delete.cpp

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+// delete.cpp -- using the delete operator
+#include <iostream>
+#include <cstring>      // or string.h
+using namespace std;
+char * getname(void);   // function prototype
+int main()
+{
+    char * name;        // create pointer but no storage
+    name = getname();   // assign address of string to name
+
+    cout << name << " at " << (int *) name << "\n";
+    delete [] name;     // memory freed
+
+    name = getname();   // reuse freed memory
+    cout << name << " at " << (int *) name << "\n";
+    delete [] name;     // memory freed again
+    // cin.get();
+    // cin.get();
+    return 0;
+}
+
+char * getname()        // return pointer to new string
+{
+    char temp[80];      // temporary storage
+    cout << "Enter last name: ";
+    cin >> temp;
+    char * pn = new char[strlen(temp) + 1];
+    strcpy(pn, temp);   // copy string into smaller space
+
+    return pn;          // temp lost when function ends
+}

source/chapter04/init_ptr.cpp

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+// init_ptr.cpp -- initialize a pointer
+#include <iostream>
+int main()
+{
+    using namespace std;
+    int higgens = 5;
+    int * pt = &higgens;
+
+    cout << "Value of higgens = " << higgens
+         << "; Address of higgens = " << &higgens << endl;
+    cout << "Value of *pt = " << *pt
+         << "; Value of pt = " << pt << endl;
+    // cin.get();
+    return 0; 
+}

source/chapter04/instr1.cpp

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+// instr1.cpp -- reading more than one string
+#include <iostream>
+int main()
+{
+    using namespace std;
+    const int ArSize = 20;
+    char name[ArSize];
+    char dessert[ArSize];
+
+    cout << "Enter your name:\n";
+    cin >> name;
+    cout << "Enter your favorite dessert:\n";
+    cin >> dessert;
+    cout << "I have some delicious " << dessert;
+    cout << " for you, " << name << ".\n";
+    // cin.get();
+	// cin.get();
+    return 0; 
+}

source/chapter04/instr2.cpp

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+// instr2.cpp -- reading more than one word with getline
+#include <iostream>
+int main()
+{
+    using namespace std;
+    const int ArSize = 20;
+    char name[ArSize];
+    char dessert[ArSize];
+
+    cout << "Enter your name:\n";
+    cin.getline(name, ArSize);  // reads through newline
+    cout << "Enter your favorite dessert:\n";
+    cin.getline(dessert, ArSize);
+    cout << "I have some delicious " << dessert;
+    cout << " for you, " << name << ".\n";
+    // cin.get();
+    return 0; 
+}

source/chapter04/instr3.cpp

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+// instr3.cpp -- reading more than one word with get() & get()
+#include <iostream>
+int main()
+{
+    using namespace std;
+    const int ArSize = 20;
+    char name[ArSize];
+    char dessert[ArSize];
+
+    cout << "Enter your name:\n";
+    cin.get(name, ArSize).get();    // read string, newline
+    cout << "Enter your favorite dessert:\n";
+    cin.get(dessert, ArSize).get();
+    cout << "I have some delicious " << dessert;
+    cout << " for you, " << name << ".\n";
+    // cin.get();
+    return 0; 
+}

source/chapter04/mixtypes.cpp

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+// mixtypes.cpp --some type combinations
+#include <iostream>
+
+struct antarctica_years_end
+{
+    int year;
+ /* some really interesting data, etc. */
+};
+
+int main()
+{
+    antarctica_years_end s01, s02, s03; 
+    s01.year = 1998;
+    antarctica_years_end * pa = &s02;
+    pa->year = 1999;
+    antarctica_years_end trio[3]; // array of 3 structures
+    trio[0].year = 2003;
+    std::cout << trio->year << std::endl;
+    const antarctica_years_end * arp[3] = {&s01, &s02, &s03};
+    std::cout << arp[1]->year << std::endl;
+    const antarctica_years_end ** ppa = arp; 
+    auto ppb = arp; // C++0x automatic type deduction
+// or else use const antarctica_years_end ** ppb = arp; 
+    std::cout << (*ppa)->year << std::endl;
+    std::cout << (*(ppb+1))->year << std::endl;
+    // std::cin.get();
+    return 0;
+}

source/chapter04/newstrct.cpp

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+// newstrct.cpp -- using new with a structure
+#include <iostream>
+struct inflatable   // structure definition
+{
+    char name[20];
+    float volume;
+    double price;
+};
+int main()
+{
+    using namespace std;
+    inflatable * ps = new inflatable; // allot memory for structure
+    cout << "Enter name of inflatable item: ";
+    cin.get(ps->name, 20);            // method 1 for member access
+    cout << "Enter volume in cubic feet: ";
+    cin >> (*ps).volume;              // method 2 for member access
+    cout << "Enter price: $";
+    cin >> ps->price;
+    cout << "Name: " << (*ps).name << endl;              // method 2
+    cout << "Volume: " << ps->volume << " cubic feet\n"; // method 1
+    cout << "Price: $" << ps->price << endl;             // method 1
+    delete ps;                        // free memory used by structure
+    // cin.get();
+    // cin.get();
+    return 0; 
+}

source/chapter04/numstr.cpp

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+// numstr.cpp -- following number input with line input
+#include <iostream>
+int main()
+{
+    using namespace std;
+    cout << "What year was your house built?\n";
+    int year;
+    cin >> year;
+    // cin.get();
+    cout << "What is its street address?\n";
+    char address[80];
+    cin.getline(address, 80);
+    cout << "Year built: " << year << endl;
+    cout << "Address: " << address << endl;
+    cout << "Done!\n";
+    // cin.get();
+    return 0; 
+}

source/chapter04/pointer.cpp

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+// pointer.cpp -- our first pointer variable
+#include <iostream>
+int main()
+{
+    using namespace std;
+    int updates = 6;        // declare a variable
+    int * p_updates;        // declare pointer to an int
+
+    p_updates = &updates;   // assign address of int to pointer
+
+// express values two ways
+    cout << "Values: updates = " << updates;
+    cout << ", *p_updates = " << *p_updates << endl;
+
+// express address two ways
+    cout << "Addresses: &updates = " << &updates;
+    cout << ", p_updates = " << p_updates << endl;
+
+// use pointer to change value
+    *p_updates = *p_updates + 1;
+    cout << "Now updates = " << updates << endl;
+    // cin.get();
+    return 0; 
+}