Basic usage of C + + STL string

First, initialize

    strings1="I Love you"; stringS2 (S1);//Initialize the S2 to a copy of S1, note that it cannot be written as a string S2; S2 (s1);    stringS3 ("value");//Initializes a s3 copy of the string value    stringS4 (6,'s');//Initialize S4 to 10 copies of character ' s '    /*Note string literals are not the same type as standard library string*/cout<<s1<<Endl; cout<<s2<<Endl; cout<<s3<<Endl; cout<<s4<<endl;

Results

Second, input

    string S6;    Getline (CIN,S6); // enter a string with spaces to test "Hello World"    cout<<s6<<Endl;
cout<< "------------------------------" <<endl;     string S5;    CIN>>s5; // enter a string without spaces "Hello World" test, found only valid characters are read to the end    of a space encounter cout<<s5<<Endl;     // deliberately put S5 and S6 upside down, if first with CIN input S5, then use Getline (CIN,S6) will have problems. 

Results

Third, access character

    cout<<s1.at () <<endl; // The AT function provides a range check that throws a Out_of_range exception when it crosses the border.    cout<<s1[]<<endl; // the subscript operator [] does not provide check access. 

Iv. Description of characteristics

1. Determine if it is empty

S1.empty ()

2. Length

string s1="12345678";
cout<<s1.length () <<endl; // . Length () and. Size () No difference, whichever is OK
Cout<<s1.size () <<endl; // size () means that it is a container, and length () indicates that it is a string

3. Redefine the length of it (more go to less fill)

    strings1="12345678"; cout<<s1<<Endl; cout<<s1.size () <<endl;//. Length () and. Size () No difference, whichever is OKS1.resize (4);//more tocout<<s1<<Endl; cout<<s1.size () <<Endl; S1.resize (6,'x');//do not write a second parameter can also becout<<s1<<Endl; cout<<s1.size () <<endl;

Basic usage of C + + STL string