C++字符串string

string定义在命名控件std中，所以需要在文件中引入命名空间

using namespace std;

定义和初始化string

string s1 = "";
string s2 = s1;
string s3 = "Hello World";
string s4(s3);
string s5("world");
string s6(4, 'A');

判断是否为空

string str = "";
if(str.empty())
{
    cout<<"str is empty"<<endl;
}else{
    cout<<"str is not empty"<<endl;
}

字符串长度

string str = "abcd";
int len = str.size();

遍历字符串

string str = "Hello World";
for(auto s : str)
{
    cout<<s<<endl;
}

字符串拼接

string str1 = "hello";
string str2 = "world";
string str3 = str1 + " "+ str2;
cout<<str3<<endl