cplusplus 模板类学习笔记

string模板的成员函数:

const char * string::data() 和 const char * string::c_str() 返回字符串数组的const类型指针，此字符串数组代表string对象。此为string转 const char* 方法。

string::erase的三种实现：

（1）string& erase (size_t pos = 0, size_t len = npos);
（2）iterator erase (const_iterator p);
（3）iterator erase (const_iterator first, const_iterator last);

string::find的四种实现：从头（左）查找，rfind则是从尾（右）查找。

string (1) size_t find (const string& str, size_t pos = 0) const noexcept;
查找string类型的子串模式。如果找到则返回第一个匹配的位置，否则返回string：：npos

c-string (2) size_t find (const char* s, size_t pos = 0) const;
查找char* 字符串，返回内容如上。

buffer (3) size_t find (const char* s, size_t pos, size_type n) const;
查找 字符数组（即不以’\0’结尾的数组）。需要指定第三个参数-查找个数n。返回值如上所述

character (4) size_t find (char c, size_t pos = 0) const noexcept;
查找一个字符的实现函数。

比较两个char* 型字符串：

reference->cstring 或 string.h -> memcmp(const void *ptr1,const void *ptr2, size_t num)；相等为0，*ptr1>*ptr2 返回1 否则返回-1.

string::replace 的7种实现

string (1)
string& replace (size_t pos, size_t len, const string& str);
string& replace (const_iterator i1, const_iterator i2, const string& str);

substring (2)
string& replace (size_t pos, size_t len,const string& str, size_t subpos, size_t sublen);
pos为开始替换的位置，len为替换的字符个数；而subpos，sublen是使用[subpos,subpos+sublen)代替前面所说范围[pos,pos+len)

c-string (3)
string& replace (size_t pos, size_t len, const char* s);
string& replace (const_iterator i1, const_iterator i2, const char* s);

buffer (4)
string& replace (size_t pos, size_t len, const char* s, size_t n);
string& replace (const_iterator i1, const_iterator i2, const char* s, size_t n);

fill (5)
string& replace (size_t pos, size_t len, size_t n, char c);
string& replace (const_iterator i1, const_iterator i2, size_t n, char c);

range (6)
template
string& replace (const_iterator i1, const_iterator i2, InputIterator first, InputIterator last);

initializer list (7)
string& replace (const_iterator i1, const_iterator i2, initializer_list il);

example:int main (){  std::string base="this is a test string.";  std::string str2="n example";  std::string str3="sample phrase";  std::string str4="useful.";  // replace signatures used in the same order as described above:  // Using positions:                 0123456789*123456789*12345  std::string str=base;           // "this is a test string."  str.replace(9,5,str2);          // "this is an example string." (1)  str.replace(19,6,str3,7,6);     // "this is an example phrase." (2)  str.replace(8,10,"just a");     // "this is just a phrase."     (3)  str.replace(8,6,"a shorty",7);  // "this is a short phrase."    (4)  str.replace(22,1,3,'!');        // "this is a short phrase!!!"  (5)  // Using iterators:                                               0123456789*123456789*  str.replace(str.begin(),str.end()-3,str3);                    // "sample phrase!!!"      (1)  str.replace(str.begin(),str.begin()+6,"replace");             // "replace phrase!!!"     (3)  str.replace(str.begin()+8,str.begin()+14,"is coolness",7);    // "replace is cool!!!"    (4)  str.replace(str.begin()+12,str.end()-4,4,'o');                // "replace is cooool!!!"  (5)  str.replace(str.begin()+11,str.end(),str4.begin(),str4.end());// "replace is useful."    (6)  std::cout << str << '\n';  return 0;}

std::operator+ (string) 对字符串的加号的重载函数

string (1)
string operator+ (const string& lhs, const string& rhs);
string operator+ (string&& lhs, string&& rhs);
string operator+ (string&& lhs, const string& rhs);
string operator+ (const string& lhs, string&& rhs);

c-string (2)
string operator+ (const string& lhs, const char* rhs);
string operator+ (string&& lhs, const char* rhs);
string operator+ (const char* lhs, const string& rhs);
string operator+ (const char* lhs, string&& rhs);

character (3)
string operator+ (const string& lhs, char rhs);
string operator+ (string&& lhs, char rhs);
string operator+ (char lhs, const string& rhs);
string operator+ (char lhs, string&& rhs);
注：两个char * 字符串相加，使用strcat（a,b）函数。

std::ralational operators(string),两项字符串比较函数的重载。

(1)
bool operator== (const string& lhs, const string& rhs);
bool operator== (const char* lhs, const string& rhs);
bool operator== (const string& lhs, const char* rhs);
(2)
bool operator!= (const string& lhs, const string& rhs);
bool operator!= (const char* lhs, const string& rhs);
bool operator!= (const string& lhs, const char* rhs);
(3)
bool operator< (const string& lhs, const string& rhs);
bool operator< (const char* lhs, const string& rhs);
bool operator< (const string& lhs, const char* rhs);
(4)
bool operator<= (const string& lhs, const string& rhs);
bool operator<= (const char* lhs, const string& rhs);
bool operator<= (const string& lhs, const char* rhs);
(5)
bool operator> (const string& lhs, const string& rhs);
bool operator> (const char* lhs, const string& rhs);
bool operator> (const string& lhs, const char* rhs);
(6)
bool operator>= (const string& lhs, const string& rhs);
bool operator>= (const char* lhs, const string& rhs);
bool operator>= (const string& lhs, const char* rhs);