目录
0-2： Write a program that, when run, writes
0-5：Is this a valid program? Why or why not?
0-9：What is the shortest valid program?
1-1：Are the following definitions valid? Why or why not?
1-2：Are the following definitions valid? Why or why not?
1-3：Is the following program valid? If so, what does it do? If not, why not?
1-4：What about this one? What if we change }}to };}in the third line from the end?
1-5：Is this program valid? If so, what does it do? If not, say why not, and rewrite it to be valid.
第0章
0-2： Write a program that, when run, writes
This (") is a quote, and this (\) is a backslash.#include <iostream>
int main() {
std::cout << "This (\") is a quote, and the (\\) is a backslash." << std::endl;
return 0;
}0-5：Is this a valid program? Why or why not?
#include <iostream>
int main() std::cout << "Hello, world!" << std::endl;
缺少花括号 { }
0-7：What about this one?
int main()
{
/* This is a comment that extends over several lines
because it uses /* and */ as its starting and ending delimiters */
std::cout << "Does this work?" << std::endl;
return 0;
}多行注释符不可以嵌套使用 /* 会和第一个*/匹配；嵌套使用会使两个/*之间的内容属于非注释内容
0-9：What is the shortest valid program?
int main(){}
0-10：Rewrite the Hello, world! program so that a newline occurs everywhere that
whitespace is allowed in the program.
#include <iostream>
int
main
(
)
{
std
::
cout
<<
"Hello, world!"
<<
std
::
endl
;
return
0
;
}第1章
一种定义字符串的方式：
std::string stars(5,'*'); // 等同于 "*****"
//第一个参数为一个整数，第二个参数为一个字符（char）字符串字面量(string literal)：string star = "***"; 字面量即为：***, 字符串即为 star。
1-1：Are the following definitions valid? Why or why not?
const std::string hello = "Hello";
const std::string message = hello + ", world" + "!";
有效定义，hello是字符串，"+"为左结合，先hello 与 ", world" 结合后，再与 "!" 结合。
1-2：Are the following definitions valid? Why or why not?
const std::string exclam = "!";
const std::string message = "Hello" + ", world" + exclam;
无效定义，因为 + 不能连接两个字符串字面量 "Hello" 和 ", world"。
1-3：Is the following program valid? If so, what does it do? If not, why not?
#include <iostream>
#include <string>
int main()
{
{ const std::string s = "a string";
std::cout << s << std::endl; }
{ const std::string s = "another string";
std::cout << s << std::endl; }
return 0;
}
有效，输出：
a string
another string
1-4：What about this one? What if we change }}to };}in the third line from the end?
#include <iostream>
#include <string>
int main()
{
{ const std::string s = "a string";
std::cout << s << std::endl;
{ const std::string s = "another string";
std::cout << s << std::endl; }}
return 0;
}
有效。有一个作用域（内部域）嵌套在外部的作用域（外部域）里面。因为内部的作用域里定义了一个变量s，使得外部域的s被隐藏。增加分号; 不改变程序的含义。
1-5：Is this program valid? If so, what does it do? If not, say why not, and rewrite it to be valid.
#include <iostream>
#include <string>
int main()
{
{ std::string s = "a string";
{ std::string x = s + ", really";
std::cout << s << std::endl; }
std::cout << x << std::endl;
}
return 0;
}
无效，x的声明在内部作用域内，不能在外部域中使用
{ std::string s = "a string";
{ std::string x = s + ", really";
std::cout << s << std::endl;
std::cout << x << std::endl; }//将花括号挪到此处
}1-6：What does the following program do if, when it asks you for input, you type two
names (for example, Samuel Beckett)? Predict the behavior before running the program,then try it.
#include <iostream>
#include <string>
int main()
{
std::cout << "What is your name? ";
std::string name;
std::cin >> name;
std::cout << "Hello, " << name << std::endl << "And what is yours? ";
std::cin >> name;
std::cout << "Hello, " << name << "; nice to meet you too!" << std::endl;
return 0;
}
What is your name? Samuel
Hello, Samuel
And what is yours? Beckett
Hello, Beckett; nice to meet you too!第2章
参考阅读：
https://github.com/bitsai/book-exercises/tree/master/Accelerated%20C%2B%2B
https://www.parkscomputing.com/accelerated-cpp-solutions/01-workingwithstrings/