C++中string的常见用法

#include 
#include 
#include 
#include 


int main()
{
	
	//string初始化
	std::string a;//缺省初始化
	std::string b{"Hello world!"}; // 聚合初始化，"Hello world!"
	std::string c("hello C++"); // "helllo C++"
	std::string d(3,'w'); // "www"
	std::string e("Hello world!",5);// "Hello"
	std::string f = { 'h','e','l','l','o' };
	std::string g(b); //复制

	//显示
	std::cout << a << std::endl;
	std::cout << b << std::endl;
	std::cout << c << std::endl;
	std::cout << d << std::endl;
	std::cout << e << std::endl;
	std::cout << f << std::endl;

	//查看字符串大小与访问元素
	std::cout <<"查看b字符串大小: " << b.size() << std::endl;
	std::cout << "访问b中下标为0的元素: " << b.at(0) << std::endl;
	b[5] = '5';
	std::cout << "b: " << b << std::endl;
	
	//比较
	std::cout << "a与b字符串内容是否相同: " << (a!=b) << std::endl;
	std::cout << "e与f字符串内容是否相同: " << (e == f) << std::endl;
	
	//拼接
	c = b + c;
	std::cout << "c: " << c << std::endl;
	std::cout << "拼接: " << b+" yunxingluoyun " << std::endl;

	//转换类型 string --> const char *
	std::cout << typeid(f).name() << std::endl;
	std::cout << typeid(f.c_str()).name() << std::endl;//const char*
	std::cout << std::is_same_v<< std::endl;

	//查找与替换
	std::cout << c.find("C")< 
结果：
 
Hello world!
hello C++
www
Hello
hello
查看b字符串大小: 12
访问b中下标为0的元素: H
b: Hello5world!
a与b字符串内容是否相同: 1
e与f字符串内容是否相同: 0
c: Hello5world!hello C++
拼接: Hello5world! yunxingluoyun
class std::basic_string,class std::allocator >
char const * __ptr64
1
18
c: Hello5world!hello cpp