第 1 章
1.1
prog1.cc 文件代碼：ios
int main()
{
return 0;
}
在prog1.cc 文件所在目錄下，依次執行下面命令：程序員
➜ Desktop CC prog1.cc ➜ Desktop a.out ➜ Desktop echo $? 0
注：這裏prog1.cc 文件所在目錄爲Desktop；shell
1.2
prog1.cc 文件代碼修改成：express
int main()
{
return -1;
}
在prog1.cc 文件所在目錄下，依次執行下面命令：ide
➜ Desktop CC prog1.cc ➜ Desktop a.out ➜ Desktop echo $? 255
注：這裏prog1.cc 文件所在目錄爲Desktop；post
1.3
#include <iostream>
int main() {
std::cout << "Hello, World" << std::endl;
return 0;
}
1.4
#include <iostream>
int main() {
std::cout << "Enter two numbers:" << std::endl;
int v1 = 0, v2 = 0;
std::cin >> v1 >> v2;
std::cout << "The product of " << v1 << " and " << v2
<< " is " << v1 * v2 << std::endl;
return 0;
}
1.5
#include <iostream>
int main() {
std::cout << "Enter two numbers:";
std::cout << std::endl;
int v1 = 0, v2 = 0;
std::cin >> v1 >> v2;
std::cout << "The sum of ";
std::cout << v1;
std::cout << " and ";
std::cout << v2;
std::cout << " is ";
std::cout << v1 + v2;
std::cout << std::endl;
return 0;
}
1.6
std::cout << "The sum of " << v1;
<< " and " << v2;
<< " is " << v1 + v2 << std::endl;
不合法，分號表示一個語句的結束。修正方法：測試
方法一：ui
std::cout << "The sum of " << v1; std::cout << " and " << v2; std::cout << " is " << v1 + v2 << std::endl;
方法二：this
std::cout << "The sum of " << v1
<< " and " << v2
<< " is " << v1 + v2 << std::endl;
1.7
#include <iostream>
/*
* 註釋對/* */不能嵌套。
* "不能嵌套"幾個字會被認爲是源碼，
* 像剩餘程序同樣處理
*/
int main() {
return 0;
}
1.8
std::cout << "/*"; // 合法，輸出：/* std::cout << "*/"; // 合法，輸出：*/ std::cout << /* "*/" */; // 不合法 // 編譯器提示warning: missing terminating '"' character // 編譯器把第一對/* "*/識別爲註釋界定符；剩餘的" */;識別爲源碼。 std::cout << /* "*/" /* "/*" */; // 合法，輸出 /* // 首（/* "*/）尾（/*" */）爲界定符；" /* "爲源碼 // /* "*/" /* "/*" */整個這句的一開始是界定符/*，編譯器把和它匹配的最近*/之間的內 // 容（ "）識別爲註釋；接着是"，標誌着下一個和它匹配的最近"之間的內容（ /* ）是字符 // 串；接着是界定符/*，編譯器把和它匹配的最近*/之間的內容（" ）識別爲註釋。 // 原則：從左往右，就近匹配。
1.9
#include <iostream>
int main() {
int sum = 0, val = 50;
while (val <= 100) {
sum += val;
++val;
}
std::cout << "Sum of 50 to 100 inclusive is "
<< sum << std::endl;
return 0;
}
1.10
#include <iostream>
int main() {
int val = 10;
while (val >= 0) {
std::cout << val << " ";
--val;
}
std::cout << std::endl;
return 0;
}
1.11
#include <iostream>
int main() {
int val1, val2, temp;
std::cout << "Please input two integers";
std::cin >> val1 >> val2;
if (val1 > val2) {
temp = val1;
val1 = val2;
val2 = temp;
}
++val1;
while (val1 < val2) {
std::cout << val1 << " ";
++val1;
}
std::cout << std::endl;
return 0;
}
1.12
#include <iostream>
int main() {
int sum = 0;
// for循環完成-100～+100之間全部整數累加求和
for (int i = -100; i <= 100; ++i)
sum += i;
std::cout << sum << std::endl;
return 0;
}
sum的終值是0spa
1.13
#include <iostream>
int main() {
int sum = 0;
for (int val = 50; val <= 100; ++val)
sum += val;
std::cout << "Sum of 50 to 100 inclusive is "
<< sum << std::endl;
return 0;
}
#include <iostream>
int main() {
for (int val = 10; val >= 0; --val)
std::cout << val << " ";
std::cout << std::endl;
return 0;
}
#include <iostream>
int main() {
int val1, val2, temp;
std::cout << "Please input two integers";
std::cin >> val1 >> val2;
if (val1 > val2) {
temp = val1;
val1 = val2;
val2 = temp;
}
for (++val1; val1 < val2; ++val1)
std::cout << val1 << " ";
std::cout << std::endl;
return 0;
}
1.14
while (condition) statement
while 循環的條件判斷（condition）語句在每次執行完循環體（statement）語句都會執行，判斷是否繼續執行循環體。
for (init-statement; condition; expression)
statement
for 循環的初始化語句（init-statement）在循環開始的時候執行一次，以後執行判斷語句（condition），若知足條件，則執行循環體（statement），循環體內的語句執行完後緊接着執行表達式（expression），表達式的做用通常是做用判斷語句（condition），使循環在有限次內結束，而不是無限循環。固然 init-statement、conditon和expression這三條語句也能夠爲空語句（分號不能夠省略）：
for (;;)
statement
也能夠寫多條，多條之間用逗號分隔：
#include <iostream>
int main() {
for (int i = 0, j = 0; i < 2, j < 2; ++i, ++j)
std::cout << i << " " << j << '\n';
std::cout << std::endl;
return 0;
}
while 循環的優勢是書寫簡單，缺點是程序員可能忘記在循環體（statement）內做用條件判斷語句（condition），形成無限循環；for 循環的優勢是規範、整潔，不易漏掉做用條件判斷（condition）的表達式（expression），缺點是書寫稍繁瑣。while 循環適合循環次數不肯定的情景；for 循環適合循環次數事先已知。
1.15
略
1.16
#include <iostream>
int main() {
int sum = 0, value = 0;
while (std::cin >> value) {
sum += value;
}
std::cout << "Sum is: " << sum << std::endl;
return 0;
}
1.17
若是輸入的值都相等，程序輸出相等值的個數；若是沒有重複值程序則輸出每一個數字出現次數爲1，按一次Enter，輸出上一個數字的統計結果爲1.
// 測試數據 3 3 3 3 4 // 運行結果 3 occurs 4 times // 測試數據 5 // 運行結果 4 occurs 1 times // 測試數據 6 // 運行結果 5 occurs 1 times // 測試數據 7 // 運行結果 6 occurs 1 times // 測試數據 8 // 運行結果 7 occurs 1 times
1.18
// 測試數據 100 100 100 100 100 100 1 2 3 4 5 6 7 8 // 運行結果 100 occurs 6 times 1 occurs 1 times 2 occurs 1 times 3 occurs 1 times 4 occurs 1 times 5 occurs 1 times 6 occurs 1 times 7 occurs 1 times
1.19
1.11 已經考慮到該狀況。
1.20
C++ Primer 5th source code download
Sales_item.h
/*
* This file contains code from "C++ Primer, Fifth Edition", by Stanley B.
* Lippman, Josee Lajoie, and Barbara E. Moo, and is covered under the
* copyright and warranty notices given in that book:
*
* "Copyright (c) 2013 by Objectwrite, Inc., Josee Lajoie, and Barbara E. Moo."
*
*
* "The authors and publisher have taken care in the preparation of this book,
* but make no expressed or implied warranty of any kind and assume no
* responsibility for errors or omissions. No liability is assumed for
* incidental or consequential damages in connection with or arising out of the
* use of the information or programs contained herein."
*
* Permission is granted for this code to be used for educational purposes in
* association with the book, given proper citation if and when posted or
* reproduced.Any commercial use of this code requires the explicit written
* permission of the publisher, Addison-Wesley Professional, a division of
* Pearson Education, Inc. Send your request for permission, stating clearly
* what code you would like to use, and in what specific way, to the following
* address:
*
* Pearson Education, Inc.
* Rights and Permissions Department
* One Lake Street
* Upper Saddle River, NJ 07458
* Fax: (201) 236-3290
*/
/* This file defines the Sales_item class used in chapter 1.
* The code used in this file will be explained in
* Chapter 7 (Classes) and Chapter 14 (Overloaded Operators)
* Readers shouldn't try to understand the code in this file
* until they have read those chapters.
*/
#ifndef SALESITEM_H
// we're here only if SALESITEM_H has not yet been defined
#define SALESITEM_H
// Definition of Sales_item class and related functions goes here
#include <iostream>
#include <string>
class Sales_item {
// these declarations are explained section 7.2.1, p. 270
// and in chapter 14, pages 557, 558, 561
friend std::istream& operator>>(std::istream&, Sales_item&);
friend std::ostream& operator<<(std::ostream&, const Sales_item&);
friend bool operator<(const Sales_item&, const Sales_item&);
friend bool
operator==(const Sales_item&, const Sales_item&);
public:
// constructors are explained in section 7.1.4, pages 262 - 265
// default constructor needed to initialize members of built-in type
Sales_item(): units_sold(0), revenue(0.0) { }
Sales_item(const std::string &book):
bookNo(book), units_sold(0), revenue(0.0) { }
Sales_item(std::istream &is) { is >> *this; }
public:
// operations on Sales_item objects
// member binary operator: left-hand operand bound to implicit this pointer
Sales_item& operator+=(const Sales_item&);
// operations on Sales_item objects
std::string isbn() const { return bookNo; }
double avg_price() const;
// private members as before
private:
std::string bookNo; // implicitly initialized to the empty string
unsigned units_sold;
double revenue;
};
// used in chapter 10
inline
bool compareIsbn(const Sales_item &lhs, const Sales_item &rhs)
{ return lhs.isbn() == rhs.isbn(); }
// nonmember binary operator: must declare a parameter for each operand
Sales_item operator+(const Sales_item&, const Sales_item&);
inline bool
operator==(const Sales_item &lhs, const Sales_item &rhs)
{
// must be made a friend of Sales_item
return lhs.units_sold == rhs.units_sold &&
lhs.revenue == rhs.revenue &&
lhs.isbn() == rhs.isbn();
}
inline bool
operator!=(const Sales_item &lhs, const Sales_item &rhs)
{
return !(lhs == rhs); // != defined in terms of operator==
}
// assumes that both objects refer to the same ISBN
Sales_item& Sales_item::operator+=(const Sales_item& rhs)
{
units_sold += rhs.units_sold;
revenue += rhs.revenue;
return *this;
}
// assumes that both objects refer to the same ISBN
Sales_item
operator+(const Sales_item& lhs, const Sales_item& rhs)
{
Sales_item ret(lhs); // copy (|lhs|) into a local object that we'll return
ret += rhs; // add in the contents of (|rhs|)
return ret; // return (|ret|) by value
}
std::istream&
operator>>(std::istream& in, Sales_item& s)
{
double price;
in >> s.bookNo >> s.units_sold >> price;
// check that the inputs succeeded
if (in)
s.revenue = s.units_sold * price;
else
s = Sales_item(); // input failed: reset object to default state
return in;
}
std::ostream&
operator<<(std::ostream& out, const Sales_item& s)
{
out << s.isbn() << " " << s.units_sold << " "
<< s.revenue << " " << s.avg_price();
return out;
}
double Sales_item::avg_price() const
{
if (units_sold)
return revenue/units_sold;
else
return 0;
}
#endif
main.cpp
#include <iostream>
#include "Sales_item.h"
int main() {
Sales_item book;
// 讀入 ISBN 號、售出的冊數以及銷售價格
std::cin >> book;
// 寫入 ISBN、售出的冊數、總銷售額和平均價格
std::cout << book << std::endl;
return 0;
}
Clion IDE :
// 測試數據 0-201-70353-X 4 24.99 // 運行結果 0-201-70353-X 4 99.96 24.99 Process finished with exit code 0
1.21
Sales_item.h 同1.20，main.cpp 內容以下：
#include <iostream>
#include "Sales_item.h"
int main() {
Sales_item item1, item2;
std::cin >> item1 >> item2; // 讀取一對交易記錄
std::cout << item1 + item2 << std::endl; // 打印它們的和
return 0;
}
Clion IDE :
// 測試數據 0-201-78345-X 3 20.00 0-201-78456-X 2 25.00 // 運行結果 0-201-78345-X 5 110 22 Process finished with exit code 0
1.22
Sales_item.h 同1.20，main.cpp 內容以下：
/*
* This file contains code from "C++ Primer, Fifth Edition", by Stanley B.
* Lippman, Josee Lajoie, and Barbara E. Moo, and is covered under the
* copyright and warranty notices given in that book:
*
* "Copyright (c) 2013 by Objectwrite, Inc., Josee Lajoie, and Barbara E. Moo."
*
*
* "The authors and publisher have taken care in the preparation of this book,
* but make no expressed or implied warranty of any kind and assume no
* responsibility for errors or omissions. No liability is assumed for
* incidental or consequential damages in connection with or arising out of the
* use of the information or programs contained herein."
*
* Permission is granted for this code to be used for educational purposes in
* association with the book, given proper citation if and when posted or
* reproduced.Any commercial use of this code requires the explicit written
* permission of the publisher, Addison-Wesley Professional, a division of
* Pearson Education, Inc. Send your request for permission, stating clearly
* what code you would like to use, and in what specific way, to the following
* address:
*
* Pearson Education, Inc.
* Rights and Permissions Department
* One Lake Street
* Upper Saddle River, NJ 07458
* Fax: (201) 236-3290
*/
#include <iostream>
#include "Sales_item.h"
int main()
{
Sales_item item1, item2;
std::cin >> item1 >> item2;
// first check that item1 and item2 represent the same book
if (item1.isbn() == item2.isbn()) {
std::cout << item1 + item2 << std::endl;
return 0; // indicate success
} else {
std::cerr << "Data must refer to same ISBN"
<< std::endl;
return -1; // indicate failure
}
}
Clion IDE :
// 測試數據1 0-201-78345-X 4 20.00 0-201-78345-X 5 20.00 // 運行結果1 0-201-78345-X 9 195 21.6667 Process finished with exit code 0 // 測試數據2 0-202-78222-Y 2 25.00 0-201-78111-X 2 29.00 // 運行結果2 Data must refer to same ISBN Process finished with exit code 255
注：程序結束 0 和 255 正好分別對應 return 0 和 return -1.
1.23
#include <iostream>
#include "Sales_item.h"
int main() {
Sales_item currItem, valItem;
if (std::cin >> currItem) {
int cnt = 1;
while (std::cin >> valItem) {
if (valItem.isbn() == currItem.isbn()) {
++cnt;
} else {
std::cout << currItem.isbn() << " occurs " << cnt << " times " << std::endl;
currItem = valItem;
cnt = 1;
}
}
std::cout << currItem.isbn() << " occurs " << cnt << " times " << std::endl;
}
return 0;
}
// 測試數據 0-201-78345-X 4 25.0 0-201-78345-X 1 25.0 0-201-78345-X 2 25.0 0-201-78345-X 9 25.0 0-207-78345-X 9 31.0 0-207-78345-X 3 31.0 0-202-78345-X 3 20.0 0-202-78345-X 3 20.0 // 運行結果 0-201-78345-X occurs 4 times 0-207-78345-X occurs 2 times // 接着仍能夠繼續輸入測試數據
1.24
將 exercise_23.cpp 編譯運行（代碼如 1.23），生成可執行程序。
在控制檯執行：
Last login: Wed May 29 08:17:52 on console ➜ ~ /Users/xxx/Desktop/exercise_23 </Users/xxx/Desktop/Untitled-1 >/Users/xxx/Desktop/Untitled-2 ➜ ~
Untitled-1 文檔內容爲：
0-201-78345-X 4 25.0 0-201-78345-X 1 25.0 0-201-78345-X 2 25.0 0-201-78345-X 9 25.0 0-207-78345-X 9 31.0 0-207-78345-X 3 31.0 0-202-78345-X 3 20.0 0-202-78345-X 3 20.0
Untitled-2 文檔內容爲：
0-201-78345-X occurs 4 times 0-207-78345-X occurs 2 times 0-202-78345-X occurs 2 times
注：該題考查書中知識點使用文件重定向\(P_{19}\)
1.25
Sales_item.h 同1.20，main.cpp 內容以下：
#include <iostream>
#include "Sales_item.h"
int main() {
Sales_item total; // 保存下一條交易記錄的變量
// 讀入第一條交易記錄，並確保有數據能夠處理
if (std::cin >> total) {
Sales_item trans; // 保存和的變量
// 讀入並處理剩餘交易記錄
while (std::cin >> trans) {
// 若是咱們仍在處理相同的書
if (total.isbn() == trans.isbn())
total += trans; // 更新總銷售額
else {
// 打印前一本書的結果
std::cout << total << std::endl;
total = trans; // total 如今表示下一本書的銷售額
}
}
std::cout << total << std::endl; // 打印最後一本書的結果
} else {
// 沒有輸入！警告讀者
std::cerr << "No data?!" << std::endl;
return -1; // 表示失敗
}
return 0;
}
// 測試數據 0-201-78345-X 4 25.0 0-201-78345-X 1 25.0 0-201-78345-X 2 25.0 0-201-78345-X 9 25.0 0-207-78345-X 9 31.0 0-207-78345-X 3 31.0 0-202-78345-X 3 20.0 0-202-78345-X 3 20.0 // 運行結果 0-201-78345-X 16 400 25 0-207-78345-X 12 372 31
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- 2. 第1章-SingleThreadedExecution
- 3. 第八章（1）
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