string 함수 정리

c_str.cpp

// strings and c-strings
#include <iostream>
#include <cstring>
#include <string>

int main ()
{
  std::string str ("Please split this sentence into tokens");

  char * cstr = new char [str.length()+1];
  std::strcpy (cstr, str.c_str());

  // cstr now contains a c-string copy of str

  char * p = std::strtok (cstr," ");
  while (p!=0)
  {
    std::cout << p << '\n';
    p = std::strtok(NULL," ");
  }

  delete[] cstr;
  return 0;
}

compare.cpp

// comparing apples with apples
#include <iostream>
#include <string>

int main ()
{
  std::string str1 ("green apple");
  std::string str2 ("red apple");

  if (str1.compare(str2) != 0)
    std::cout << str1 << " is not " << str2 << '\n';

  if (str1.compare(6,5,"apple") == 0)
    std::cout << "still, " << str1 << " is an apple\n";

  if (str2.compare(str2.size()-5,5,"apple") == 0)
    std::cout << "and " << str2 << " is also an apple\n";

  if (str1.compare(6,5,str2,4,5) == 0)
    std::cout << "therefore, both are apples\n";

  return 0;
}

substr.cpp

// string::substr
#include <iostream>
#include <string>

int main ()
{
  std::string str="We think in generalities, but we live in details.";
                                           // (quoting Alfred N. Whitehead)

  std::string str2 = str.substr (3,5);     // "think"

  std::size_t pos = str.find("live");      // position of "live" in str

  std::string str3 = str.substr (pos);     // get from "live" to the end

  std::cout << str2 << ' ' << str3 << '\n';

  return 0;
}

c_str

string->char*

const char* c_str() const noexcept;

compare

비교하려는 대상 그대로 비교, 비교하는 문자열 또는 비교 대상 문자열 내의 문자열 비교, string과 char형과 비교

string
int compare (const string& str) const noexcept;
substring
int compare (size_t pos, size_t len, const string& str) const;
int compare (size_t pos, size_t len, const string& str, size_t subpos, size_t sublen = npos) const;
c_string
int compare (const char* s) const;
int compare (size_t pos, size_t len, const char* s) const;
buffer
int compare (size_t pos, size_t len, const char* s, size_t n) const;

substr

데이터의 내부 문자열을 가져온다.

string substr (size_t pos = 0, size_t len = npos) const;