String类（下）

// push_back
int main()
{
  string str("hello world");
  cout << str << endl;
  str.push_back('!');
  cout << str << endl;
  return 0;
}

// append
int main()
{
  string str1;
  string str2("hello");
  string str3("world");
  // append(const string& str)
  str1.append(str2);
  cout << str1 << endl;
  // append(const string& str, size_t subpos, size_t sublen)
  str1.append(str1, 2, 2);
  cout << str1 << endl;
  // append(const char* s)
  str1.append("!!!");
  cout << str1 << endl;
  // append(const char* s, size_t n)
  str1.append("world", 4);
  cout << str1 << endl;
  // append(size_t n, char c)
  str1.append(3, '?');
  cout << str1 << endl;
  return 0;
}

// operator+=
int main()
{
  string str1("hello");
  string str2("world");
  str1 += " c++ ";
  str1 += str2;
  str1 += '!';
  cout << str1 << endl;
  return 0;
}

// insert()
int main()
{
  string str1 = "hello ";
  string str2 = "world";
  string str3 = "c/c++";
  string::iterator it;
  // string& insert(size_t pos, const string& str)
  str1.insert(6, str2);
  cout << str1 << endl;
  // string& inser(size_t pos, const string& str, size_t subpos, size_t sublen)
  str1.insert(6, str3, 2, 3);
  cout << str1 << endl;
  // string& insert(size_t pos, const char* s)
  str1.insert(5, " vue");
  cout << str1 << endl;
  // string& insert(size_t pos, const char* s, size_t n)
  str1.insert(5, " javascipt", 5);
  cout << str1 << endl;
  // string& insert(size_t pos, size_t n, char c)
  str1.insert(0, 3, '!');
  cout << str1 << endl;
  // void insert(iterator p, size_t n, char c)
  str1.insert(str1.end(), 3, '!');
  cout << str1 << endl;
  // iterator insert(iterator p, char c)
  it = str1.insert(str1.begin() + 3, ' ');
  cout << str1 << endl;
  return 0;
}

// replace
int main()
{
  string str1("in me the tiger ");
  string str2("sniffs the rose");
  string str3("hello world");
  string str4("love");
  // string& replace(size_t pos, size_t len, const string& str)
  str1.replace(10, 6, str2);
  cout << str1 << endl;
  // string& replace(iterator i1, iterator i2, const string& str)
  str1.replace(str1.begin(), str1.end() - 5, str3);
  cout << str1 << endl;
  // string& replace(size_t pos, size_t len, const string& str, size_t subpos, size_t sublen)
  str1.replace(6, 5, str2, 0, 6);
  cout << str1 << endl;
  // string& replace(size_t pos, size_t len, const char* s)
  str1.replace(6, 6, "mood");
  cout << str1 << endl;
  // string& replace(iterator i1, iterator i2, const char* s)
  str1.replace(str1.begin(), str1.begin() + 5, "iterator");
  cout << str1 << endl;
  // string& replace(size_t pos, size_t len, const char* s, size_t n)
  str1.replace(2, 6, " good job", 5);
  cout << str1 << endl;
  // string& replace(iterator i1, iterator i2, const char* s, size_t n)
  str1.replace(str1.begin(), str1.begin() + 2, "capacity", 3);
  cout << str1 << endl;
  // string& replace(size_t pos, size_t len, size_t n, char c)
  str1.replace(0, 3, 3, 's');
  cout << str1 << endl;
  // string& replace(iterator i1, iterator i2, size_t n, char c)
  str1.replace(str1.end() - 4, str1.end(), 3, '!');
  cout << str1 << endl;
  return 0;
}

// swap
int main()
{
  string str1("hello");
  string str2("world");
  cout << str1 << " " << str2 << endl;
  printf("%p %p\n", &str1, &str2);
  str1.swap(str2);
  cout << str1 << " " << str2 << endl;
  printf("%p %p\n", &str1, &str2);
  return 0;
}

// c_str
int main()
{
  string s1("hello world");
  cout << s1 << endl;
  cout << s1.c_str() << endl;
  cout << (void*)s1.c_str() << endl;
  cout << s1 << endl;
  cout << s1.c_str() << endl;
  s1 += '\0';
  s1 += '\0';
  s1 += "xxxxx";
  cout << s1 << endl;
  cout << s1.c_str() << endl;
  return 0;
}

// find
int main()
{
  string str1("in me the tiger sniffs the rose");
  string str2("tiger");
  // size_t find(const string& str, size_t pos = 0) const;
  size_t found = str1.find(str2);
  if (found != string::npos)
    cout << found << endl;
  // size_t find(const char* s, size_t pos = 0) const;
  found = str1.find("sniffs");
  if (found != string::npos)
    cout << found << endl;
  // size_t find(const char* s, size_t pos, size_t n) const;
  found = str1.find("the tiger", 8, 3);
  if (found != string::npos)
    cout << found << endl;
  // size_t find(char c, size_t pos = 0) const;
  found = str1.find('t');
  if (found != string::npos)
    cout << found << endl;
  return 0;
}

// substr
int main()
{
  string str1("in me the tiger sniffs the rose");
  string str2 = str1.substr(3, 2);
  cout << str2 << endl;
  size_t pos = str1.find("tiger");
  string str3 = str1.substr(pos);
  cout << str3 << endl;
  return 0;
}

// operator+
int main()
{
  string firstlevel("com");
  string secondlevel("cplusplus");
  string scheme("http://");
  string hostname;
  string url;
  hostname = " www." + secondlevel + '.' + firstlevel;
  url = scheme + hostname;
  cout << url << endl;
  return 0;
}

// getline
int main()
{
  string name;
  getline(cin, name);
  cout << "Hello, " << name << endl;
  return 0;
}

// relational operators
int main()
{
  string str1("alpha");
  string str2("beta");
  if (str1 == str2)
    cout << "equal" << endl;
  if (str1 != str2)
    cout << "not equal" << endl;
  if (str1 < str2)
    cout << "less" << endl;
  if (str1 > str2)
    cout << "greater" << endl;
  if (str1 <= str2)
    cout << "less or equal" << endl;
  if (str1 >= str2)
    cout << "greater or equal" << endl;
  return 0;
}