fig19_09.cpp

来自「这是C＋＋编程经典的书上实例的源代码。 （英文名是《C＋＋ how to pr」· C++ 代码 · 共 56 行

// Fig. 19.9: fig19_09.cpp
// Converting to C-style strings.
#include <iostream>

using std::cout;
using std::endl;

#include <string>

using std::string;

int main()
{
   string s( "STRINGS" );
   const char *ptr1 = 0;
   int len = s.length();
   char *ptr2 = new char[ len + 1 ]; // including null
   
   // copy characters out of string into allocated memory
   s.copy( ptr2, len, 0 );
   ptr2[ len ] = 0;  // add null terminator

   // output 
   cout << "string s is " << s 
        << "\ns converted to a C-Style string is "
        << s.c_str() << "\nptr1 is ";

   // Assign to pointer ptr1 the const char * returned by
   // function data(). NOTE: this is a potentially dangerous
   // assignment. If the string is modified, the pointer
   // ptr1 can become invalid.
   ptr1 = s.data();  
   
   for ( int k = 0; k < len; ++k )
      cout << *( ptr1 + k );   // use pointer arithmetic

   cout << "\nptr2 is " << ptr2 << endl;
   delete [] ptr2;
   return 0;
}

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