[学习笔记][C++Primer Plus]String类的使用

1.构造字符串

//1. string(const char * s)

string one("This is a string");

cout << one << endl;

//2. string(size_type n, char c)

string two(20,'$');

cout << two << endl;

//3.string(const string &str, string size_type pos=0, size_type n = npos)

string three(one);

cout << three << endl;

one += ". hello world";

cout << one << endl;

two = "Change two";

cout << two << endl;

three[0] = 'P';

cout << three << endl;

//4. string()

string four;

four = two + three;

cout << four << endl;

//5. string(const char *s, size_type n)

char alls[] = "abcdefghijklmnopqrstuvwxyz";

string five(alls,20);

cout << five << endl;

//6. template<class Iter)

//7. string(Iter begin, Iter end)

string six(alls+6,alls+10);

cout << six << endl;

string seven(&five[6], &five[10]);

cout << seven << endl;

输出结果如下：

This is a string
$$$$$$$$$$$$$$$$$$$$
This is a string
This is a string. hello world
Change two
Phis is a string
Change twoPhis is a string
abcdefghijklmnopqrst
ghij
ghij
Press any key to continue

2.输入字符串

// C风格的字符串，如果长度大于10会怎么样？

char info[10];

cin >> info;

cin.getline(info,10);

cin.get(info, 10);

string word;

cout << "Enter a line: ";

cin >> word;

while(cin.get()!='\n')

{

continue;

}

cout << word << " is all I wanted." << endl;

string line;

cout << "Enter a line (really!): ";

getline(cin, line); // 使用getline(istream &, string &)

cout << "Line: " << line << endl;

输出结果：

Enter a line: aaaaa bbbbb ccccc ddddddd
aaaaa is all I wanted.
Enter a line (really!): aaaaa bbbbb ccccc ddddddd
Line: aaaaa bbbbb ccccc ddddddd