empty

Syntax:

    #include <string>
    bool empty() const;

The empty() function returns true if the string has no elements, false otherwise. For example:
如果 string 对象没有元素，empty()函数返回 true, 否则返回 false。例如:

    string s1;
    string s2("");
    string s3("This is a string");
    cout.setf(ios::boolalpha);
    cout << s1.empty() << endl;
    cout << s2.empty() << endl;
    cout << s3.empty() << endl;

When run, this code produces the following output:
运行后，代码会产生如下输出：

    true
    true
    false

Related Topics: size