C++/String/string copy

Материал из C\C++ эксперт
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Copy char array from a string to a char pointer

  
 
#include <iostream>
using std::cout;
using std::endl;
#include <string>
using std::string;
int main()
{
   string string1( "STRINGS" );
   int length = string1.length();
   char *ptr2 = new char[ length + 1 ];
   string1.copy( ptr2, length, 0 );
   ptr2[ length ] = "\0";
   cout << "\nptr2 is " << ptr2 << endl;
   delete [] ptr2;
   return 0;
}
/* 
ptr2 is STRINGS
 */


Copying Strings

  
#include <iostream>
#include <string>
using namespace std;
int main( )
{
   string s1( "this is a test" );
   string s1_copy;
   s1_copy = s1;
   string s1_duplicate( s1 );
   cout << "String 1:             " << s1
        << "\nCopy of String 1:     " << s1_copy
        << "\nDuplicate of String1: " << s1_duplicate;
   string s2( "B" );
   cout << "\n\nString 2:  " << s2;
   s1 = s2.substr( 0, 6 );
   cout << s1;
}


Initializing, Assigning (Copying), and Concatenating Strings Using std::string

  
#include <string>
#include <iostream>
int main ()
{
   std::string str1 ("This is a C++ string! ");
   std::cout << "str1 = " << str1 << std::endl;
   std::string str2;
   str2 = str1;
   std::cout << "Result of assignment, str2 = " << str2 << std::endl;
   str2 = "Hello string!";
   std::cout << "After over-writing contents, str2 = " << str2;
   std::string strAddResult = str1 + str2;
   std::cout << strAddResult;
   return 0;
}


STL string Instantiation and Copy Techniques

  
#include <string>
#include <iostream>
using namespace std;
int main ()
{
   const char* pChar = "Hello String!";
   cout << pChar << endl;
   std::string strFromConst (pChar);
   cout << strFromConst << endl;
   std::string str2 ("Hello String!");
   std::string str2Copy (str2);
   cout << str2Copy << endl;
   // Initialize a string to the first 5 characters of another
   std::string subString (pChar, 5);
   cout << subString << endl;
   return 0;
}