在 C++ 中声明多行字符串
本文将介绍几种在 C++ 中如何声明多行字符串的方法。
使用 std::string 类在 C++ 中声明多行字符串
std::string 对象可以用一个字符串值初始化。在这种情况下，我们将 s1 字符串变量声明为 main 函数的一个局部变量。C++ 允许在一条语句中自动连接多个双引号的字符串字元。因此，在初始化 string 变量时，可以包含任意行数，并保持代码的可读性更一致。
#include <iostream>
#include <string>
#include <vector>
#include <iterator>
using std::cout; using std::vector;
using std::endl; using std::string;
using std::copy;
int main(){
string s1 = "This string will be printed as the"
" one. You can include as many lines"
"as you wish. They will be concatenated";
copy(s1.begin(), s1.end(),
std::ostream_iterator<char>(cout, ""));
cout << endl;
return EXIT_SUCCESS;
}
输出：
This string will be printed as the one. You can include as many linesas you wish. They will be concatenated
使用 const char *符号来声明多行字符串文字
但在大多数情况下，用 const 修饰符声明一个只读的字符串文字可能更实用。当相对较长的文本要输出到控制台，而且这些文本大多是静态的，很少或没有随时间变化，这是最实用的。需要注意的是，const 限定符的字符串在作为 copy 算法参数传递之前需要转换为 std::string 对象。
#include <iostream>
#include <string>
#include <vector>
#include <iterator>
using std::cout; using std::cin;
using std::endl; using std::string;
using std::vector; using std::copy;
int main(){
const char *s2 =
"This string will be printed as the"
" one. You can include as many lines"
"as you wish. They will be concatenated";
string s1(s2);
copy(s1.begin(), s1.end(),
std::ostream_iterator<char>(cout, ""));
cout << endl;
return EXIT_SUCCESS;
}
输出：
This string will be printed as the one. You can include as many linesas you wish. They will be concatenated
使用 const char *符号与反斜杠字声明多行字符串文字
另外，也可以利用反斜杠字符/来构造一个多行字符串文字，并将其分配给 const 限定的 char 指针。简而言之，反斜杠字符需要包含在每个换行符的末尾，这意味着字符串在下一行继续。
不过要注意，间距的处理变得更容易出错，因为任何不可见的字符，如制表符或空格，可能会将被包含在输出中。另一方面，人们可以利用这个功能更容易地在控制台显示一些模式。
#include <iostream>
#include <string>
#include <vector>
#include <iterator>
using std::cout; using std::cin;
using std::endl; using std::string;
using std::vector; using std::copy;
int main(){
const char *s3 = " This string will\n\
printed as the pyramid\n\
as one single string literal form\n";
cout << s1 << endl;
printf("%s\n", s3);
return EXIT_SUCCESS;
}
输出：
This string will
printed as the pyramid
as one single string literal form
Founder of DelftStack.com. Jinku has worked in the robotics and automotive industries for over 8 years. He sharpened his coding skills when he needed to do the automatic testing, data collection from remote servers and report creation from the endurance test. He is from an electrical/electronics engineering background but has expanded his interest to embedded electronics, embedded programming and front-/back-end programming.
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