如题所述
string类的查找函数：
int find(char c, int pos = 0) const;//从pos开始查找字符c在当前字符串的位置
int find(const char *s, int pos = 0) const;//从pos开始查找字符串s在当前串中的位置
int find(const char *s, int pos, int n) const;//从pos开始查找字符串s中前n个字符在当前串中的位置
int find(const string &s, int pos = 0) const;//从pos开始查找字符串s在当前串中的位置
//查找成功时返回所在位置，失败返回string::npos的值
int rfind(char c, int pos = npos) const;//从pos开始从后向前查找字符c在当前串中的位置
int rfind(const char *s, int pos = npos) const;
int rfind(const char *s, int pos, int n = npos) const;
int rfind(const string &s,int pos = npos) const;
//从pos开始从后向前查找字符串s中前n个字符组成的字符串在当前串中的位置，成功返回所在位置，失败时返回string::npos的值
int find_first_of(char c, int pos = 0) const;//从pos开始查找字符c第一次出现的位置
int find_first_of(const char *s, int pos = 0) const;
int find_first_of(const char *s, int pos, int n) const;
int find_first_of(const string &s,int pos = 0) const;
//从pos开始查找当前串中第一个在s的前n个字符组成的数组里的字符的位置。查找失败返回string::npos
int find_first_not_of(char c, int pos = 0) const;
int find_first_not_of(const char *s, int pos = 0) const;
int find_first_not_of(const char *s, int pos,int n) const;
int find_first_not_of(const string &s,int pos = 0) const;
//从当前串中查找第一个不在串s中的字符出现的位置，失败返回string::npos
int find_last_of(char c, int pos = npos) const;
int find_last_of(const char *s, int pos = npos) const;
int find_last_of(const char *s, int pos, int n = npos) const;
int find_last_of(const string &s,int pos = npos) const;
int find_last_not_of(char c, int pos = npos) const;
int find_last_not_of(const char *s, int pos = npos) const;
int find_last_not_of(const char *s, int pos, int n) const;
int find_last_not_of(const string &s,int pos = npos) const;
//find_last_of和find_last_not_of与find_first_of和find_first_not_of相似，只不过是从后向前查找
int find(char c, int pos = 0) const;//从pos开始查找字符c在当前字符串的位置
int find(const char *s, int pos = 0) const;//从pos开始查找字符串s在当前串中的位置
int find(const char *s, int pos, int n) const;//从pos开始查找字符串s中前n个字符在当前串中的位置
int find(const string &s, int pos = 0) const;//从pos开始查找字符串s在当前串中的位置
//查找成功时返回所在位置，失败返回string::npos的值
int rfind(char c, int pos = npos) const;//从pos开始从后向前查找字符c在当前串中的位置
int rfind(const char *s, int pos = npos) const;
int rfind(const char *s, int pos, int n = npos) const;
int rfind(const string &s,int pos = npos) const;
//从pos开始从后向前查找字符串s中前n个字符组成的字符串在当前串中的位置，成功返回所在位置，失败时返回string::npos的值
int find_first_of(char c, int pos = 0) const;//从pos开始查找字符c第一次出现的位置
int find_first_of(const char *s, int pos = 0) const;
int find_first_of(const char *s, int pos, int n) const;
int find_first_of(const string &s,int pos = 0) const;
//从pos开始查找当前串中第一个在s的前n个字符组成的数组里的字符的位置。查找失败返回string::npos
int find_first_not_of(char c, int pos = 0) const;
int find_first_not_of(const char *s, int pos = 0) const;
int find_first_not_of(const char *s, int pos,int n) const;
int find_first_not_of(const string &s,int pos = 0) const;
//从当前串中查找第一个不在串s中的字符出现的位置，失败返回string::npos
int find_last_of(char c, int pos = npos) const;
int find_last_of(const char *s, int pos = npos) const;
int find_last_of(const char *s, int pos, int n = npos) const;
int find_last_of(const string &s,int pos = npos) const;
int find_last_not_of(char c, int pos = npos) const;
int find_last_not_of(const char *s, int pos = npos) const;
int find_last_not_of(const char *s, int pos, int n) const;
int find_last_not_of(const string &s,int pos = npos) const;
//find_last_of和find_last_not_of与find_first_of和find_first_not_of相似，只不过是从后向前查找
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第1个回答 推荐于2017-09-08
通常来说，用于寻找某个序列的在string中第一次出现的位置。
find函数有以下四种重载版本：
size_t find (const string& str, size_t pos = 0) const noexcept;size_t find (const char* s, size_t pos = 0) const;
size_t find (const char* s, size_t pos, size_type n) const;
size_t find (char c, size_t pos = 0) const noexcept;
参数说明：
str/s/c：要寻找的序列，可以是（版本1），也可以是字符串字面值或者说C风格字符串（版本2、3，在版本3中，所寻找的序列是从s[0]开始的前n个字符），也可以是字符（版本4）。
pos：从string的pos位置开始寻找（注意第一个位置是0）。
函数返回序列第一次出现的位置，如果没有找到则返回string::npos。
样例：（摘自cplusplus.com）
#include <iostream> // std::cout#include <string> // std::string
int main ()
{
std::string str ("There are two needles in this haystack with needles.");
std::string str2 ("needle");
// different member versions of find in the same order as above:
std::size_t found = str.find(str2);
if (found!=std::string::npos)
std::cout << "first 'needle' found at: " << found << '\n';
found=str.find("needles are small",found+1,6);
if (found!=std::string::npos)
std::cout << "second 'needle' found at: " << found << '\n';
found=str.find("haystack");
if (found!=std::string::npos)
std::cout << "'haystack' also found at: " << found << '\n';
found=str.find('.');
if (found!=std::string::npos)
std::cout << "Period found at: " << found << '\n';
// let's replace the first needle:
str.replace(str.find(str2),str2.length(),"preposition");
std::cout << str << '\n';
return 0;
}
标准输出结果：
first 'needle' found at: 14
second 'needle' found at: 44
'haystack' also found at: 30
Period found at: 51
There are two prepositions in this haystack with needles.
第2个回答 2012-03-05
std::basic_string::find
size_type find( const basic_string& str, size_type pos = 0 );
(1)
size_type find( const CharT* s, size_type pos, size_type count );
(2)
size_type find( const CharT* s, size_type pos = 0 );
(3)
size_type find( CharT ch, size_type pos = 0 );
(4)
Finds the first substring equal to the given character sequence. Search begins at pos, i.e. the found substring must not begin in a position preceding pos.
1) Finds the first substring equal to str.
2) Finds the first substring equal to the first count characters of the character string pointed to by s. s can include null characters.
3) Finds the first substring equal to the character string pointed to by s. The length of the string is determined by the first null character.
4) Finds the first character ch.
size_type find( const basic_string& str, size_type pos = 0 );
(1)
size_type find( const CharT* s, size_type pos, size_type count );
(2)
size_type find( const CharT* s, size_type pos = 0 );
(3)
size_type find( CharT ch, size_type pos = 0 );
(4)
Finds the first substring equal to the given character sequence. Search begins at pos, i.e. the found substring must not begin in a position preceding pos.
1) Finds the first substring equal to str.
2) Finds the first substring equal to the first count characters of the character string pointed to by s. s can include null characters.
3) Finds the first substring equal to the character string pointed to by s. The length of the string is determined by the first null character.
4) Finds the first character ch.
第3个回答 2008-09-25
CString::Find
int Find( TCHAR ch ) const;
int Find( LPCTSTR lpszSub ) const;
int Find( TCHAR ch, int nStart ) const;
int Find( LPCTSTR pstr, int nStart ) const;
Return Value
The zero-based index of the first character in this CString object that matches the requested substring or characters; -1 if the substring or character is not found.
这是我从MSDN上COPY下来的
意思是说从第nStart个字符开始查找字符ch或字符串pstr。
找到的话返回值是ch在CString这个字符串中的位置
找不到的话返回值-1
zero-based index就是说字符串的第一个字符串对应的nstart是0
比如说
CString test="asdfjkll";
test.find('c')的值是-1
test.find('d')的值是2
…………
int Find( TCHAR ch ) const;
int Find( LPCTSTR lpszSub ) const;
int Find( TCHAR ch, int nStart ) const;
int Find( LPCTSTR pstr, int nStart ) const;
Return Value
The zero-based index of the first character in this CString object that matches the requested substring or characters; -1 if the substring or character is not found.
这是我从MSDN上COPY下来的
意思是说从第nStart个字符开始查找字符ch或字符串pstr。
找到的话返回值是ch在CString这个字符串中的位置
找不到的话返回值-1
zero-based index就是说字符串的第一个字符串对应的nstart是0
比如说
CString test="asdfjkll";
test.find('c')的值是-1
test.find('d')的值是2
…………
第4个回答 2008-09-25
不是很难的东西，不用翻译了吧，From MSDN：
CString::Find
int Find( TCHAR ch ) const;
int Find( LPCTSTR lpszSub ) const;
int Find( TCHAR ch, int nStart ) const;
int Find( LPCTSTR pstr, int nStart ) const;
Return Value
The zero-based index of the first character in this CString object that matches the requested substring or characters; -1 if the substring or character is not found.
Parameters
ch
A single character to search for.
lpszSub
A substring to search for.
nStart
The index of the character in the string to begin the search with, or 0 to start from the beginning. The character at nStart is excluded from the search if nStart is not equal to 0.
pstr
A pointer to a string to search for.
Remarks
Searches this string for the first match of a substring. The function is overloaded to accept both single characters (similar to the run-time function strchr) and strings (similar to strstr).
Example
// First example demonstrating
// CString::Find ( TCHAR ch )
CString s( "abcdef" );
ASSERT( s.Find( 'c' ) == 2 );
ASSERT( s.Find( "de" ) == 3 );
// Second example demonstrating
// CString::Find( TCHAR ch, int nStart )
CString str("The stars are aligned");
int n = str.Find('e', 5);
ASSERT(n == 12);
CString::Find
int Find( TCHAR ch ) const;
int Find( LPCTSTR lpszSub ) const;
int Find( TCHAR ch, int nStart ) const;
int Find( LPCTSTR pstr, int nStart ) const;
Return Value
The zero-based index of the first character in this CString object that matches the requested substring or characters; -1 if the substring or character is not found.
Parameters
ch
A single character to search for.
lpszSub
A substring to search for.
nStart
The index of the character in the string to begin the search with, or 0 to start from the beginning. The character at nStart is excluded from the search if nStart is not equal to 0.
pstr
A pointer to a string to search for.
Remarks
Searches this string for the first match of a substring. The function is overloaded to accept both single characters (similar to the run-time function strchr) and strings (similar to strstr).
Example
// First example demonstrating
// CString::Find ( TCHAR ch )
CString s( "abcdef" );
ASSERT( s.Find( 'c' ) == 2 );
ASSERT( s.Find( "de" ) == 3 );
// Second example demonstrating
// CString::Find( TCHAR ch, int nStart )
CString str("The stars are aligned");
int n = str.Find('e', 5);
ASSERT(n == 12);
