C++ string 클래스 부분 (출처 : winapi.co.kr)
template<class _Elem, class _Traits = char_traits<_Elem>, class _Ax = allocator<_Elem> > class basic_string { 멤버 목록 };_Elem과 _Traits는 iostream에서 봤던 부분
_Elem은 데이터 타입. 여기서도 문자열.
_Traits는 문자열 표시하는 방법 BSTR과 널종료문자열.
_Ax는 _Ax 인수는 문자열 관리를 위한 메모리를 어떻게 할당하고 해제할 것인가를 지정하는 할당기이다.
디폴트인 allocator<_Elem>은 C++의 할당 연산자인 new, delete를 사용하는데 원한다면 다른 것으로 바꿀 수 있다.
typedef basic_string<char> string; typedef basic_string<wchar_t> wstring;
템플릿 인수는 가급적 실제 인수로 표기하고 중간 타입들은 평이한 타입으로 바꿔서 표기하기로 하는데
_Elem => 그냥 char
size_type => size_t(결국 unsigned)
생성자
| 원형 | 설명 |
| string() | 디폴트 생성자. 빈 문자열을 만든다. |
| string(const char *s) | 널 종료 문자열로부터 생성하는 변환 생성자 |
| string(const string &str, int pos=0, int num=npos) | 복사 생성자 |
| string(size_t n, char c) | c를 n개 가득 채움 |
| string(const char *s, size_t n) | 널 종료 문자열로부터 생성하되 n길이 확보 |
| template<It> string(It begin, It end) | begin~end사이의 문자로 구성된 문자열 생성 |
#include <Turboc.h>
#include <iostream>
#include <string>
using namespace std;
void main()
{
string s("C++ string");
cout << s << " 문자열의 길이 = " << s.size() << endl; // ①
cout << s << " 문자열의 길이 = " << s.length() << endl; // ②
cout << s << " 문자열의 할당 크기 = " << s.capacity() << endl; // ③
cout << s << " 문자열의 최대 길이 = " << s.max_size() << endl; // ④
s.resize(6);
cout << s << " 길이 = " << s.size() << ",할당 크기 = " << s.capacity() << endl; // ⑤
s.reserve(100);
cout << s << " 길이 = " << s.size() << ",할당 크기 = " << s.capacity() << endl; // ⑥
}
/*
C++ string 문자열의 길이 = 10
C++ string 문자열의 길이 = 10
C++ string 문자열의 할당 크기 = 15
C++ string 문자열의 최대 길이 = 4294967294
C++ st 길이 = 6,할당 크기 = 15
C++ st 길이 = 6,할당 크기 = 111
*/
size와 length는 객체에 저장된 문자열의 길이를 조사하는데 strlen 표준 함수와 기능상 동일하다. 널 종료 문자는 빼고 문자의 개수가 리턴된다. 역사적인 이유로 똑같은 함수가 두 개 제공되는데 length는 표준 이전의 길이 조사 함수이고 size는 STL이 표준이 된 후 STL과 함수명을 일관되게 맞추기 위해 새로 만들어진 것이다. 둘 중 편한대로 사용하면 된다. capacity 객체가 할당한 메모리의 양을 조사
max_size 함수는 문자열 객체가 가질 수 있는 최대 길이를 조사하는데 32비트 시스템에서 이 값은 unsigned의 최대값보다 1 작은 값이다.
max_size가 리턴하는 값은 string::npos 정적 멤버 변수로 정의되어 있는데 이 값은 (unsigned)-1과 같다.
실제 객체가 이 길이를 가질 수 없으므로 npos는 검색 함수가 실패를 리턴할 때 흔히 사용된다.
resize 함수는 문자열의 길이를 인수로 전달된 개수로 강제 조정한다. 예를 들면, s1.resize(15,'*');를 호출하면 "C++ string*****"가 된다
reserve 함수는 메모리의 여유분을 지정한 크기만큼 미리 확보한다.
void clear( ); bool empty( ) const;
data 함수는 string 객체의 네이티브 데이터 번지를 그대로 리턴하므로 널 종료 문자가 아닐 수도 있지만 c_str은 항상 널 종료 문자열이다.
data는 객체의 내부 데이터를 그대로 리턴하는 것이고 c_str은 널 종료 문자열이 아닌 경우 사본을 복사한 후 널 종료 문자열로 바꿔서 리턴한다는 점이 다르다.
물론 string 클래스는 널 종료 문자열이므로 string 객체에 대해서는 data와 c_str이 같겠지만 다른 basic_string 템플릿 클래스에서는 결과가 달라질 수도 있다. 그래서 C 스타일의 문자 배열로 string 객체를 복사하고 싶을 때는 c_str 멤버 함수를 사용하는 것이 옳다.
입출력
template<class _Elem, class _Traits, class _Alloc> inline basic_ostream<_Elem, _Traits>& __cdecl operator<<(basic_ostream<_Elem, _Traits>& _Ostr, const basic_string<_Elem, _Traits, _Alloc>& _Str);
좀 편하게 보자면
ostream& operator<<(ostream& cout, string &s);
char& operator[](size_type _Off) char& at(size_type _Off); const char& operator[](size_type _Off) const const char& at(size_type _Off) const;
string& operator=(char ch); string& operator=(const char* str); string& operator=(const string& other);
string& operator+=(char ch); string& operator+=(const char* str); string& operator+=(const string& other);두 문자열을 합친 길이만큼 메모리를 재할당할 것이다.
string& assign(const string& _str, size_t off, size_t count); // C++의 strncpy() string& append(const string& _str, size_t off, size_t count);
size_type copy(value_type* _Ptr, size_type _Count, size_type _Off = 0) const; void swap(basic_string& _Str);copy 함수는 대상이 현객체에서 _Ptr로 복사 시킨다.
문자 배열 객체인 _Ptr의 _Off 이후에 있는 문자들을 _Count 개수만큼 복사한다.
swap은 말그대로 교환한다.
string& insert(size_t pos, const char* ptr); string& insert(size_t pos, const char* ptr, size_t count); string& insert(size_t pos, const string& str); string& insert(size_t pos, const string& str, int off, int count); string& insert(size_t pos, int count, char ch); void push_back(char ch);append는 첫 번째 인수가 size()인 insert라고 할 수 있다.
string& erase(size_t pos=0, size_t count=npos);
string& replace(size_t pos, size_t num, const char *ptr);
string substr(size_t off=0, size_t count=npos); const;off 위치에서부터 count 개수만큼의 부분 문자열을 추출하여 새로운 string 객체를 만들며 원본 객체는 건드리지 않는다.
int compare(const string& str) const; int compare(size_t pos, size_t num, const string& str) const; int compare(size_t pos, size_t num, const string& str, size_t off, size_t count) const;두 번째 원형은 호출 객체의 일부를 str 전체와 비교하며 세 번째 원형은 호출 객체 일부와 str의 일부를 비교한다.
size_t find(char ch, size_t off=0) const; size_t find(const char* ptr, size_t off=0) const; size_t find(const char* ptr, size_t off=0, size_t count) const; size_t find(const string& str, size_t off=0) const;string 객체의 off위치에서 문자, 문자열, 다른 string 객체를 찾아 그 첨자 위치를 리턴한다.
발견되지 않을 경우 -1로 정의되어 있는 string::npos를 리턴하므로 이 값과 상등 연산해 보면 검색 대상의 존재 여부를 알 수 있다.
rfind는 역방향으로 검색한다.
find_first_of(string &str); find_last_of(string &str); find_first_not_of(string &str); find_last_not_of(string &str);인수로 주어진 문자열을 구성하는 문자 중 하나를 순방향, 역방향으로 찾거나 아니면 구성 문자가 아닌 최초의 문자를 검색한다.
최초의 모음이나 숫자 또는 특정 문자군에 속한 문자를 찾고 싶을 때 이 함수들이 유용하다.
string s1("starcraft");
string moum("aeiou");
cout << "최초의 모음" << s1.find_first_of(moum) << "번째" << endl; constructors 1.
#include <iostream> #include <string> using namespace std; int main () { char *line = "short line for testing"; // with no arguments string s1; s1 = "Anatoliy"; cout << "s1 is: " << s1 << endl; // copy constructor string s2 (s1); cout << "s2 is: " << s2 << endl; // one argumen string s3 (line); cout << "s3 is: " << s3 << endl; // first argumen C string // second number of characters string s4 (line,10); cout << "s4 is: " << s4 << endl; // 1 - C++ string // 2 - start position // 3 - number of characters string s5 (s3,6,4); // copy word 'line' from s3 cout << "s5 is: " << s5 << endl; // 1 - number characters // 2 - character itself string s6 (15,'*'); cout << "s6 is: " << s6 << endl; // 1 - start iterator // 2 - end iterator string s7 (s3.begin(),s3.end()-5); cout << "s7 is: " << s7 << endl; // you can instantiate string with assignment string s8 = "Anatoliy"; cout << "s8 is: " << s8 << endl; return 0; } OUTPUT: // s1 is: Anatoliy // s2 is: Anatoliy // s3 is: short line for testing // s4 is: short line // s5 is: line // s6 is: *************** // s7 is: short line for te // s8 is: Anatoliy getline 1.
/* 1 getline ( intut_stream, str, delim ); Extracts characters from intut_stream and stores them in str until s.max_size() characters have been extracted, the end of file occurs, or delim is encountered, in which case delim is extracted from istr but is not stored in s 2 getline( Iter, str ) Inputs a string value for str as in the preceding func� tion with delim = */#include <iostream> #include <string> #include <vector> #include <fstream> using namespace std; int main () { string str; cout << "Enter string (EOL = $) : "; getline (cin, str, '$'); cout << "Str is : " << str << endl; ifstream In("data.dat"); vectorv; cout << endl << "Read data from file" << endl; while ( ! In.eof() ) { getline (In, str); v.push_back(str); } copy (v.begin(),v.end(), ostream_iterator (cout,"\n")); cout << endl; return 0; } OUTPUT: // Enter string (EOL = $) : Str is : first line // second line$ // // Read data from file // file: "data.dat" // second line // last line << >> operators 1.
#include <iostream> #include <string> using namespace std; int main () { string str; cout << "Enter string for testing : "; cin >> str; cout << "\nString is : " << str << endl; cout << "Enter string for testing " << "(d to quit) : "; while ( cin >> str ) { cout << endl; cout << "String is : " << str << endl; cout << "Enter string for testing " << "( d to quit) : "; } return 0; } OUTPUT: // Enter string for testing : first // String is : first // Enter string for testing ( d to quit) : second // String is : second // Enter string for testing ( + += = operators 1.d to quit) : third // String is : third // Enter string for testing ( d to quit) :
#include <iostream> #include <string> using namespace std; int main () { string str = "Hello"; cout << "str is : " << str << endl; str += ","; str += ' '; cout << "str is : " << str << endl; string s; s = str + "World"; cout << "s is : " << s << endl; char ch = '!'; s += ch; cout << "s is : " << s << endl; return 0; } OUTPUT: // str is : Hello // str is : Hello, // s is : Hello, World // s is : Hello, World! append 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "Nobody is perfect"; string s = ""; // empty string char *ch = "abcdef"; // append string str at the end of s; // return s // appends at the end of s a copy of the n characters // in str, starting at position pos; if n is too // large, characters are copied only until the end // of str is reached; // returns s s.append(str,0,6); cout << "s is : " << s << endl; // appends copies of the characters in the range [inpIt1, // inpIt2] to s; returns s string::iterator inpIt1 = str.begin()+6; //start from ' is' string::iterator inpIt2 = str.end(); s.append(inpIt1,inpIt2); cout << "s is : " << s << endl; // appends three ! s.append(3,'!'); cout << "s is : " << s << endl; // appends the first n characters in ch at the end // of s; returns s s.append(ch,3); cout << "s is : " << s << endl; // appends charArray at the end of s; returns s s.append(ch,3); cout << "s is : " << s << endl; return 0; } OUTPUT: // s is : Nobody // s is : Nobody is perfect // s is : Nobody is perfect!!! // s is : Nobody is perfect!!!abc // s is : Nobody is perfect!!!abcabc assign 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "Nobody is perfect"; string s = ""; char *ch = "Robert Frost"; // assigns a copy of str to s; returns s s.assign(str); cout << "s is : " << s << endl; // assigns to s a copy of the n characters in str, start� // ing at position 10: if n is too large, characters are // copied only until the end of str is reached: returns s s.assign(str,10,7); // perfect cout << "s is : " << s << endl; // assigns to s a string consisting of the first n charac� // ters in ch: returns s s.assign(ch,6); cout << "s is : " << s << endl; // assigns to s a copy of ch: returns s s.assign(ch); cout << "s is : " << s << endl; // assigns to s a string consisting of the characters in // the range str.begin(), str.end(); returns s s.assign(str.begin(),str.end()); cout << "s is : " << s << endl; // assigns to s a string consisting of n copies of ch; // returns s s.assign(17,'*'); cout << "s is : " << s << endl; return 0; } OUTPUT: // s is : Nobody is perfect // s is : perfect // s is : Robert // s is : Robert Frost // s is : Nobody is perfect // s is : ***************** at 1.
// returns s[pos]#include <iostream> #include <string> using namespace std; int main () { string s = "Nobody is perfect"; // Returns s[pos] for ( int pos = 0; pos < s.length(); ++pos ) cout << s.at(pos) << " "; cout << endl; return 0; } OUTPUT: // N o b o d y i s p e r f e c t begin 1.
// Returns an iterator positioned at the // first character in a string#include <iostream> #include <string> using namespace std; int main () { string str = "C++ is best computer language"; string::iterator It = str.begin(); while ( It != str.end() ) { if ( *It == ' ' ) *It = '\n'; cout << *It++; } cout << endl; return 0; } OUTPUT: // C++ // is // best // computer // language c_str 1.
// returns (the base address of) a char // array containing the characters stored in s, // terminated by a null character.#include <iostream> #include <string> using namespace std; int main () { string str = "Anatoliy"; char *ary = new char[str.length()+1]; // strcpy ( ary, str ); that is wrong way strcpy ( ary, str.c_str() ); // that is correct cout << ary << endl; return 0; } OUTPUT: // Anatoliy capacity 1.
// returns the size (of type size_type) // of the storage allocated in string#include <iostream> #include <string> using namespace std; int main () { string str = "C++ is best computer language"; string::size_type cap; cap = str.capacity(); cout << "Capacity of str is: " << cap << endl; cout << "Size of str is : " << str.size() << endl; cout << "Length of str is : " << str.length() << endl; cout << "Resize the str for 50 character" << endl; str.resize(50); cap = str.capacity(); cout << "Capacity of str is: " << cap << endl; cout << "Size of str is : " << str.size() << endl; cout << "Length of str is : " << str.length() << endl; return 0; } OUTPUT: // Capacity of str is: 32 // Size of str is : 29 // Length of str is : 29 // Resize the str for 50 character // Capacity of str is: 64 // Size of str is : 50 // Length of str is : 50 compare 1.
#include <iostream> #include <string> using namespace std; int main () { string str1 = "string"; string str2 = "String"; string str3 = "second string"; char ch[] = "first string"; cout << "string str1 is : " << str1 << endl; cout << "string str2 is : " << str2 << endl; cout << "char ary ch is : " << ch << endl; cout << "string str3 is : " << str3 << endl; cout << endl; // compare str1 and str2 cout << "1." << endl; size_t comp = str1.compare(str2); cout << "String str1 is "; ( comp == 0 ) ? cout << "equal" : cout << "not equal"; cout << " to string str2" << endl; // compare str1 and literal string "string" cout << "2." << endl; comp = str1.compare("string"); cout << "String str1 is "; ( comp == 0 ) ? cout << "equal" : cout << "not equal"; cout << " to array of char \"string\"" << endl; // 3. and 4. doesn't work with Microsoft // Visual Studio compiler // compare str3 start from pos 7 to 5 // with str1 cout << "3." << endl; comp = str3.compare(str1,7,5); cout << "Part of string str3 is "; ( comp == 0 ) ? cout << "equal" : cout << "not equal"; cout << " to str1" << endl; // compare str3 start from pos 7 // with literal string "string" cout << "4." << endl; comp = str3.compare("string",7); cout << "Part of string str3 is "; ( comp == 0 ) ? cout << "equal" : cout << "not equal"; cout << " to C string \"string\"" << endl; // next 4 'compare' functions // doesn't work with GNU compiler cout << "5." << endl; comp = str1.compare(6,10,ch); cout << "String str1 is "; ( comp == 0 ) ? cout << "equal" : cout << "not equal"; cout << " to part of char ary \"first string\"" << endl; cout << "6." << endl; comp = str1.compare(0,3,str3); cout << "Part of str1 is "; ( comp == 0 ) ? cout << "equal" : cout << "not equal"; cout << " to string \"second string\"" << endl; cout << "7." << endl; comp = str1.compare(1,3,str2,1,3); cout << "String str1 is "; ( comp == 0 ) ? cout << "equal" : cout << "not equal"; cout << " to part of string \"second string\"" << endl; cout << "8." << endl; comp = str1.compare(1,3,str2,1,3); cout << "String str1 is "; ( comp == 0 ) ? cout << "equal" : cout << "not equal"; cout << " to part of string \"second string\"" << endl; return 0; } OUTPUT: GNU compiler // string str1 is : string // string str2 is : String // char ary ch is : first string // string str3 is : second string // // 1. // String str1 is not equal to string str2 // 2. // String str1 is equal to array of char "string" // 3. // Part of string str3 is equal to str1 // 4. // Part of string str3 is equal to C string "string" // 5. // 6. // 7. // 8. OUTPUT: Microsoft Visual Studio compiler // string str1 is : string // string str2 is : String // char ary ch is : first string // string str3 is : second string // // 1. // String str1 is not equal to string str2 // 2. // String str1 is equal to array of char "string" // 3. // 4. // 5. // String str1 is not equal to part of char ary "first // string" // 6. // Part of str1 is not equal to string "second string" // 7. // String str1 is equal to part of string "second string" // 8. // String str1 is equal to part of string "second string" // Press any key to continue copy 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "First Name: Robert"; char fname[255]; cout << "str is: " << str << endl; int n = str.find(':'); str.copy(fname, // copy to array n+1, // how many char 0); // start position from str // must terminate fname with '\0'; fname[n+1] = 0; cout << "fname is: " << fname << endl; return 0; } OUTPUT: // str is: First Name: Robert // fname is: First Name: empty 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "*******"; while ( ! str.empty() ) { cout << str << endl; str.erase(str.end()-1); } cout << endl; return 0; } OUTPUT: // ******* // ****** // ***** // **** // *** // ** // * end 1.
// returns an iterator porsitioned immediately // after the last character in string#include <iostream> #include <string> using namespace std; int main () { string s; string str = "*************************"; size_t pos = str.length(); while ( pos ) { s.assign ( str.begin(),str.end() - pos+1); cout << s << endl; pos -= 5; } return 0; } OUTPUT: // * // ****** // *********** // **************** // ********************* erase 1.
#include <iostream> #include <string> #include <algorithm> using namespace std; int main () { string str, s; for ( char ch = 'a'; ch <= 'z'; ch++ ) str.append(1,ch); s = str; cout << "str is: " << str << endl; cout << "s is: " << str << endl; // removes 13 characters from the beginning str.erase(0,13); cout << "Erased range fron str : " << str << endl; // removes 13 characters starts from 14 str = s.erase(13,13); cout << "Erased range from s : " << str << endl; // removes one character pointed by s.begin() cout << endl << "Erase one, second character from s" << endl; s.erase(s.begin()+1); cout << "s is: " << s << endl; // removes range of characters s.erase(s.begin(),s.begin()+4); cout << "s is: " << s << endl; return 0; } OUTPUT: // str is: abcdefghijklmnopqrstuvwxyz // s is: abcdefghijklmnopqrstuvwxyz // Erased range fron str : nopqrstuvwxyz // Erased range from s : abcdefghijklm // // Erase one, second character from s // s is: acdefghijklm // s is: fghijklm find 1.
#include <iostream> #include <string> #include <algorithm> using namespace std; int main () { string str("C++ is best language"); int pos1, pos2; // size_t or size_type // work not correct // search for first string "best" inside of str // default position is 0 pos1 = str.find ("best"); cout << "Word best is found on position " << pos1+1 << endl; // if pattern is not found - return -1 pos2 = str.find ("best",pos1+1); cout << "Word best is found on position " << pos2+1 << endl; // search for first occurrence of character pos1 = str.find('g'); cout << "First character 'g' found on position " << pos1 << endl; // search for first occurrence of string string s = "is"; pos1 = str.find (s); cout << "Word 'is' is found on position " << pos1+1 << endl; return 0; } OUTPUT: // Word best is found on position 8 // Word best is found on position 0 // First character 'g' found on position 15 // Word 'is' is found on position 5 find_first_not_of 1.
#include <iostream> #include <string> using namespace std; int main () { string str("C++ is best language"); cout << "str is: " << str << endl; int n = str.find_first_not_of("aeiouAEIOU"); cout << "First consonant found at " << n+1 << " position" << endl; return 0; } OUTPUT: // str is: C++ is best language // First consonant found at 1 position find_first_not_of 2.
#include <iostream> #include <string> using namespace std; int main () { string str("C++ is best language"); cout << "str is: " << str << endl; // search first not ' ', // start from position 7 int n = str.find_first_not_of(' ',7); cout << "first not of space character " << "found at position " << n+1 << endl; return 0; } OUTPUT: // str is: C++ is best language // first not of space character found at position 8 find_first_not_of 3.
#include <iostream> #include <string> using namespace std; int main () { string str("C++ is best language"); string s = "C++"; cout << "str is: " << str << endl; // search character from pattern // using the first x ch�acters in pattern. // the value position must be given int n = str.find_first_not_of("CBCD",0,3); cout << "first not 'C' is found at position " << n+1 << endl; // search first not of // pattern is string n = str.find_first_not_of(s); cout << "first not of C++ is found " << "at position " << n+1 << endl; return 0; } OUTPUT: // str is: C++ is best language // first not 'C' is found at position 2 // first not of C++ is found at position 4 find_first_of 1.
#include <iostream> #include <string> using namespace std; int main () { string str("C++ is best language"); string s = "be"; cout << "str is: " << str << endl; // search be start from position 2 // if position is ommited - default is 0 int n = str.find_first_of(s,2); cout << "first 'be' found at position " << n+1 << endl; // same as above but search for character n = str.find_first_of('l'); cout << "first character 'l' found at " << "position " << n+1 << endl; // search 'first of' for the characters in // charary char charary[] = " bea"; cout << "charary[] = \" bea\"" << endl; n = str.find_first_of(charary,0); cout << "first character from charary " << "found at position " << n+1 << endl; cout << "Note: position 4 is space" << endl; // same as above but third argumen is // number of character from which searching // starts // this variant of find_first_of dosn't // work properly with GNU compiler n = str.find_first_of(" bae",0,3); cout << "first character from charary " << "found at position " << n+1 << endl; return 0; } OUTPUT: // str is: C++ is best language // first 'be' found at position 8 // first character 'l' found at position 13 // charary[] = " bea" // first character from charary found at position 4 // Note: position 4 is space // first character from charary found at position 4 find_last_not_of 1.
#include <iostream> #include <string> using namespace std; int main () { string str("C++ is best language"); string s = "langue"; int pos = str.length()-1; cout << "str is: " << str << endl; // returns the highest position <= pos of a character // in str that does not match any charcter in s; // returns nopos if there is no such position: // npos is the default value for pos int n = str.find_last_not_of(s, pos); cout << "last_not_of 'langue' found at position " << n+1 << endl; // same as above but search for single character n = str.find_last_not_of('e'); cout << "last_not_of 'e' found at position " << n+1 << endl; char ary[] = "be"; // seawrch for occurence last_not_of // from pattern ary in str n = str.find_last_not_of(ary); cout << "last_not_of 'be' found at position " << n+1 << endl; return 0; } OUTPUT: // str is: C++ is best language // last_not_of 'langue' found at position 12 // last_not_of 'e' found at position 19 // last_not_of 'be' found at position 19 find_last_of 1.
#include <iostream> #include <string> using namespace std; int main () { string str("C++ is best language"); string s = "g"; cout << "str is: " << str << endl; cout << "s is: " << s << endl; int n = str.find_last_of(s); cout << "last_of '" << s << "' faund" << " at position " << n+1 << endl; n = str.find_last_of(' '); cout << "last_of ' ' faund" << " at position " << n+1 << endl; n = str.find_last_of(" la"); cout << "last_of \" la\" faund" << " at position " << n+1 << endl; return 0; } OUTPUT: // str is: C++ is best language // s is: g // last_of 'g' faund at position 19 // last_of ' ' faund at position 12 // last_of " la" faund at position 18 insert 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "C++ language"; string s = "is best"; char ch[] = "C++ language"; cout << "str is: " << str << endl; cout << "s is: " << s << endl; cout << "ch is: " << s << endl; // insert a copy of s into str // at position pos; string::size_type pos = 4; str.insert(pos,s); cout << "str is: " << str << endl; // insert a copy of ch into str at // the position specified by iterator // return an iterator positioned at // this copy int n = str.find('l'); str.insert(str.begin() + n,' '); cout << "str is: " << str << endl; // like above but n x copies of char str.insert(str.end(),3,'!'); cout << "str is: " << str << endl; // insert 4 char from ch into s // at the position 0 s.insert(0,ch,4); cout << "s is: " << s << endl; // insert 8 characters from str // start from position n ('langu...') // into s at position x (end string) n = str.find('l'); int x = s.length(); s.insert(x,str,n,8); cout << "s is: " << s << endl; n = s.find('l'); s.insert(s.begin()+n,' '); cout << "s is: " << s << endl; // insert range (begin - begin+7) of str // into s at position begin+4 s.insert(s.begin()+4,str.begin(),str.begin()+7); cout << "s is: " << s << endl; return 0; } OUTPUT: // str is: C++ language // s is: is best // ch is: is best // str is: C++ is bestlanguage // str is: C++ is best language // str is: C++ is best language!!! // s is: C++ is best // s is: C++ is bestlanguage // s is: C++ is best language // s is: C++ C++ is is best language length 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "C++ is best computer language"; cout << "str is: " << str << endl; cout << "Length of str is : " << str.length() << endl; return 0; } OUTPUT: // str is: C++ is best computer language // Length of str is : 29 max_size 1.
// returns a reverse iterator positioned // at the last character in string#include <iostream> #include <string> using namespace std; int main () { string str = "C++ is best computer language"; cout << "str is: " << str << endl; cout << "max_size of str is: " << str.max_size() << endl; return 0; } OUTPUT: // str is: C++ is best computer language // max_size of str is: 4294967294 rbegin 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "C++ is best computer language"; cout << "str is: " << str << endl; // usual iterator doesn't work string::reverse_iterator It = str.rbegin(); while ( It != str.rend() ) cout << *It++; cout << endl; return 0; } OUTPUT: // str is: C++ is best computer language // egaugnal retupmoc tseb si ++C replace 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "STL is created from Dennis Ritchie"; string s1 = "was"; string s2 = "developed"; string s3 = "Stepanov alexander"; cout << "str is: " << str << endl; cout << "replace 'is' for 'was'" << endl; str.replace(4, // start position in str 2, // how many characters s1); // source for replasment cout << "str is: " << str << endl; cout <<"replace 'created' for 'developed'" << endl; int n = str.find('c'); // pos of 'created' int x = str.find("from") -1; str.replace(str.begin()+n,// start pointer str.begin()+x, // end pointer s2); // source cout << "str is: " << str << endl; cout << "replace 'Dennis' for 'alexander'" << endl; int x1 = str.find('D'); // search Dennis int x2 = str.find(' ',x1+1); // space after int y1 = s3.find("alex"); // search 'alex' int y2 = strlen("alexander"); str.replace(x1, // start position in str x2-x1, // how characters to replace s3, // source for replacement y1, // start positio from source y2); // how chracter start from y1 cout << "str is: " << str << endl; cout << "replace 'from' for 'by'" << endl; char ary[] = "bytes"; n = str.find("from"); // same variant possible with iterators // instead of number of position str.replace(n, // start position in str 4, // how many characters ary, // source 2); // first 2 characters from source cout << "str is: " << str << endl; cout << "replace 'a' for 'A' (alexander)" << endl; n = str.find("alexander"); str.replace(n, // start position in str 1, // how character(s) 1, // how many copies of character 'A'); // character for replasment cout << "str is: " << str << endl; cout << "replace 'Ritchie' for 'Stepanov'" << endl; x1 = str.find('R'); y1 = s3.find(' '); str.replace(str.begin()+x1, // start pointer str.end(), // to the end of str s3.begin(), // start pointer from source s3.begin()+y1 // end pointer from ); // source cout << "str is: " << str << endl; return 0; } OUTPUT: // str is: STL is created from Dennis Ritchie // replace 'is' for 'was' // str is: STL was created from Dennis Ritchie // replace 'created' for 'developed' // str is: STL was developed from Dennis Ritchie // replace 'Dennis' for 'alexander' // str is: STL was developed from alexander Ritchie // replace 'from' for 'by' // str is: STL was developed by alexander Ritchie // replace 'a' for 'A' (alexander) // str is: STL was developed by Alexander Ritchie // replace 'Ritchie' for 'Stepanov' // str is: STL was developed by Alexander Stepanov reverse 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "Anatoliy Urbanskiy"; cout << str.reverse() << endl; return 0; } OUTPUT: resize 1.
// if <=s.size(), truncates rightmost // character in s to make it of size n; otherwise, adds // copies of character ch to end of s to increase it size // to n, or adds a default character value (usually a // blank) if ch is omitted; return type is void#include <iostream> #include <string> using namespace std; int main () { string str = "Alexander Stepanov"; cout << "str is: " << str << endl; cout << "size of str is: " << str.size() << endl; str.resize(11); cout << "after str.resize(11)" << endl; cout << "str is: " << str << endl; cout << "size of str is: " << str.size() << endl; str.resize(20,'.'); cout << "after str.resize(20,'.')" << endl; cout << "str is: " << str << endl; cout << "size of str is: " << str.size() << endl; return 0; } OUTPUT: // str is: Alexander Stepanov // size of str is: 18 // after str.resize(11) // str is: Alexander S // size of str is: 11 // after str.resize(9,'.') // str is: Alexander S......... // size of str is: 20 rfind 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "We go step by step to the target"; string s1 = "step"; cout << "str is: " << str << endl; cout << "s1 is: " << s1 << endl; cout << "int n1 = str.find(s1)" << endl; int n1 = str.find(s1); cout << "n1 = " << n1+1 << endl; cout << "int n2 = str.rfind(s1)" << endl; int n2 = str.rfind(s1); cout << "n2 = " << n2+1 << endl; cout << "n3 = str.rfind(s1,n2-1)" << endl; int n3 = str.rfind(s1,n2-1); cout << "n3 = " << n3+1 << endl; cout << "n1 = str.rfind('t')" << endl; n1 = str.rfind('t'); cout << "n1 = " << n1+1 << endl; cout << "n2 = str.rfind('t',n1-1)" << endl; n2 = str.rfind('t',n1-1); cout << "n2 = " << n2+1 << endl; char ch[] = "step"; cout << "char ch[] = \"step\"" << endl; cout << "n1 = str.rfind(ch)" << endl; n1 = str.rfind(ch); cout << "n1 = " << n1+1 << endl; cout << "n2 = str.rfind(\"stabc\",10,2)" << endl; n2 = str.rfind("stabc", // pattern 10, // start position 2); // for first 2 char // in pattern cout << "n2 = " << n2+1 << endl; return 0; } OUTPUT: // str is: We go step by step to the target // s1 is: step // int n1 = str.find(s1) // n1 = 7 // int n2 = str.rfind(s1) // n2 = 15 // n3 = str.rfind(s1,n2-1) // n3 = 7 // n1 = str.rfind('t') // n1 = 32 // n2 = str.rfind('t',n1-1) // n2 = 27 // char ch[] = "step" // n1 = str.rfind(ch) // n1 = 15 // n2 = str.rfind("stabc",10,2) // n2 = 7 size 1.
#include <iostream> #include <string> using namespace std; int main () { string str = "We go step by step to the target"; string::size_type size = str.size(); cout << "str is: " << str << endl; cout << "size of str = " << size << endl; return 0; } OUTPUT: // str is: We go step by step to the target // size of str = 32 substr 1.
// str.subsr(pos,n); // returns a copy of the substring consisting // of n characters from str, beginning at position pos // (default value 0); if n is too large or is omitted, // characters are copied only until the end of s is // reached#include <iostream> #include <string> using namespace std; int main () { string str = "We go step by step to the target"; cout << "str is: " << str << endl; int n = str.find("step"); string s = str.substr(n); cout << "s is: " << s << endl; s = str.substr(n,12); cout << "s is: " << s << endl; return 0; } OUTPUT: // str is: We go step by step to the target // s is: step by step to the target // s is: step by step swap 1.
#include <iostream> #include <string> using namespace std; int main () { string str1 = "Robert"; string str2 = "Forest"; cout << "str1 is: " << str1 << endl; cout << "str2 is: " << str2 << endl; cout << endl; cout << "str1.swap(str2)" << endl; cout << endl; str1.swap(str2); cout << "str1 is: " << str1 << endl; cout << "str2 is: " << str2 << endl; return 0; } OUTPUT: // str1 is: Robert // str2 is: Forest // // str1.swap(str2) // // str1 is: Forest // str2 is: Robert