C++ Tutorial/string/string char array

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Convert string to C-Style string

#include <iostream>
using std::cout;
using std::endl;
#include <string>
using std::string;
int main()
{
   string string1( "STRINGS" );
   cout << "string string1 is " << string1
      << "\nstring1 converted to a C-Style string is "
      << string1.c_str() << "\n";

   return 0;
}
string string1 is STRINGS
string1 converted to a C-Style string is STRINGS

Delete characters from the string given position and count

#include <string>
#include <algorithm>
#include <iostream>
using namespace std;
int main ()
{
    string strSample ("Hello String! Wake up to a beautiful day!");
    strSample.erase (13, 28);
    cout << strSample;
    return 0;
}

If character found, "erase" to deletes a character

#include <string>
#include <algorithm>
#include <iostream>
using namespace std;
int main ()
{
    string strSample ("Hello String!");
    // Find a character "S" in the string using STL find algorithm
    string::iterator iCharS = find ( strSample.begin (), strSample.end (), "S");
    // If character found, "erase" to deletes a character
    cout << "Erasing character "S" from the sample string:" << endl;
    if (iCharS != strSample.end ())
        strSample.erase (iCharS);
    cout << strSample;
 
    return 0;
}

Insert character to the end of a string

#include <string>
#include <iostream>
using namespace std;
int main(int argc, char** argv)
{
  string str1;
  str1.insert(str1.end(), "h");
  str1.insert(str1.end(), "e");
  str1.insert(str1.end(), "l");
  str1.insert(str1.end(), "l");
  str1.insert(str1.end(), "o");
  for (string::const_iterator it = str1.begin(); it != str1.end(); ++it) {
    cout << *it;
  }
  cout << endl;
  return (0);
}

Locating all instances of a character

#include <string>
#include <iostream>
using namespace std;
int main ()
{
    string strSample ("Good day String!");
    // Find substring "day" in it...
    size_t nOffset = strSample.find ("day", 0);
    cout << "Locating all instances of character "a"" << endl;
    const char chCharToSearch = "a";
    size_t nCharacterOffset = strSample.find (chCharToSearch, 0);
    while (nCharacterOffset != string::npos)
    {
        cout << """ << chCharToSearch << "" found";
        cout << " at position: " << nCharacterOffset << endl;
       // Make the "find" function search forward from the next character onwards
        size_t nCharSearchOffset = nCharacterOffset + 1;
        nCharacterOffset = strSample.find(chCharToSearch,nCharSearchOffset);
    }
    return 0;
}

String array

#include <iostream>
#include <string>
using namespace std;
int main()
{
  string sentence, words[10];
  int pos = 0, old_pos = 0, nwords, i = 0;
  sentence = "Eskimos have 23 ways to ";
    sentence += "describe snow";
  while (pos < sentence.size()) {
    pos = sentence.find(" ", old_pos);
    words[i++].assign(sentence, old_pos, pos - old_pos);
    cout << words[i - 1] << endl; //print words
    old_pos = pos + 1;
  }
  nwords = i;
  sentence = "C++ programmers ";
  for (i = 1; i < nwords -1; ++i)
    sentence += words[i] + " ";
  sentence += "windows";
  cout << sentence << endl;
}

Use push_back() to add characters to a string

#include <iostream>
#include <string>
using namespace std;
int main()
{
  string str1("A");
  string str2("B");
  string str3("G");
  string str4;
  cout << "  str1: " << str1 << endl;
  cout << "  str2: " << str2 << endl;
  cout << "  str3: " << str3 << "\n\n";
  // Use push_back() to add characters to str4.
  for(char ch = "A"; ch <= "Z"; ++ch)
    str4.push_back(ch);
  cout << "str4 after calls to push_back(): " << str4 << endl;
  cout << "Size and capacity of str4 is now " << str4.size() << " " << str4.capacity() << "\n\n";
  return 0;
}
Источник — «http://cppe.ru/index.php?title=C%2B%2B_Tutorial/string/string_char_array&oldid=2747»