chap7.lst

The Art of C++一书的配套源代码

 
  // Copy existing elements to new array, 
  // inserting new element if possible. 
  for(i=j=0; i < size(); i++, j++) { 
    if(&arrayptr[i] == p) {  
      tmp[j] = val; 
      q = &tmp[j]; 
      j++; 
    } 
    tmp[j] = arrayptr[i]; 
  } 
 
  // Otherwise, the new element goes on end. 
  if(p == end()) { 
    tmp[j] = val; 
    q = &tmp[j]; 
  } 
 
  // Adjust len and bounds. 
  len++; 
  if(p < &arrayptr[abs(lowerbound)]) 
    lowerbound--; 
  else  
    upperbound++; 
 
  // Call destructors for elements in old container. 
  for(size_type i=0; i < size()-1; i++) 
    a.destroy(&arrayptr[i]); 
 
  // Release memory for old container. 
  a.deallocate(arrayptr, size()-1); 
 
  arrayptr = tmp; 
 
  return q; 
} 
 
// Erase element at p. 
template <class T, class A> 
typename RangeArray<T, A>::iterator  
RangeArray<T, A>::erase(iterator p) 
{     
  iterator q = p; 
 
  // Destruct element being erased.  
  if(p != end()) a.destroy(p); 
 
  // Adjust len and bounds. 
  len--; 
  if(p < &arrayptr[abs(lowerbound)])  
    lowerbound++; 
  else  
    upperbound--; 
 
  // Compact remaining elements. 
  for( ; p < end(); p++) 
    *p = *(p+1); 
 
  return q; 
} 
 
 
// ********  Relational Operators ************** 
 
template<class T, class Allocator> 
  bool operator==(const RangeArray<T, Allocator> &a, 
                  const RangeArray<T, Allocator> &b) 
{ 
  if(a.size() != b.size()) return false; 
 
  return equal(a.begin(), a.end(), b.begin()); 
} 
 
template<class T, class Allocator> 
  bool operator!=(const RangeArray<T, Allocator> &a, 
                  const RangeArray<T, Allocator> &b) 
{ 
  if(a.size() != b.size()) return true; 
 
  return !equal(a.begin(), a.end(), b.begin()); 
} 
 
template<class T, class Allocator> 
  bool operator<(const RangeArray<T, Allocator> &a, 
                 const RangeArray<T, Allocator> &b) 
{ 
  return lexicographical_compare(a.begin(), a.end(), 
                                 b.begin(), b.end()); 
} 
 
template<class T, class Allocator> 
  bool operator>(const RangeArray<T, Allocator> &a, 
                 const RangeArray<T, Allocator> &b) 
{ 
  return b < a; 
} 
 
template<class T, class Allocator> 
  bool operator<=(const RangeArray<T, Allocator> &a, 
                 const RangeArray<T, Allocator> &b) 
{ 
  return !(a > b); 
} 
 
template<class T, class Allocator> 
  bool operator>=(const RangeArray<T, Allocator> &a, 
                 const RangeArray<T, Allocator> &b) 
{ 
  return !(a < b); 
}

listing 2
// Demonstrate basic RangeArray operations. 
#include <iostream> 
#include <algorithm> 
#include <functional> 
#include "ra.h" 
using namespace std; 
 
// Display integers -- for use by for_each. 
void display(int v) 
{ 
  cout << v << " "; 
}   
 
int main() 
{ 
  RangeArray<int> ob(-5, 5, 0); 
  RangeArray<int>::iterator p; 
  int i, sum; 
 
  cout << "Size of ob is: " << ob.size() << endl; 
 
  cout << "Initial contents of ob:\n"; 
  for(i=-5; i <= 5; i++) cout << ob[i] << " "; 
  cout << endl; 
 
  // Give ob some values. 
  for(i=-5; i <= 5; i++) ob[i] = i; 
 
  cout << "New values for ob: \n"; 
  p = ob.begin(); 
  do { 
    cout << *p++ << " "; 
  } while (p != ob.end()); 
  cout << endl; 
 
  // Display sum of negative indexes. 
  sum = 0; 
  for(i = ob.getlowerbound(); i < 0; i++) 
    sum += ob[i]; 
  cout << "Sum of values with negative subscripts is: "; 
  cout << sum << "\n\n"; 
 
  // Use copy() algorithm to copy one object to another. 
  cout << "Copy ob to ob2 using copy() algorithm.\n"; 
 
  RangeArray<int> ob2(-5, 5, 0); 
  copy(ob.begin(), ob.end(), ob2.begin()); 
 
  // Use for_each() algorithm to display ob2. 
  cout << "Contents of ob2: \n"; 
  for_each(ob2.begin(), ob2.end(), display);  
  cout << "\n\n"; 
 
  // Use replace_copy_if() algorithm to remove values less than zero. 
  cout << "Replace values less than zero with zero.\n";  
  cout << "Put the result into ob3.\n"; 
  RangeArray<int> ob3(ob.begin(), ob.end()); 
 
  // The next line uses the function object less() and 
  // the binder bind2nd(). 
  replace_copy_if(ob.begin(), ob.end(), ob3.begin(), 
                  bind2nd(less<int>(), 0), 0); 
  cout << "Contents of ob3: \n"; 
  for_each(ob3.begin(), ob3.end(), display); 
  cout << "\n\n"; 
 
  cout << "Swap ob and ob3.\n"; 
  ob.swap(ob3); // swap ob and ob3 
  cout << "Here is ob3:\n"; 
  for_each(ob3.begin(), ob3.end(), display); 
  cout << endl; 
  cout << "Swap again to restore.\n"; 
  ob.swap(ob3); // restore  
  cout << "Here is ob3 after second swap:\n"; 
  for_each(ob3.begin(), ob3.end(), display); 
  cout << "\n\n"; 
 
  // Use insert() member functions. 
  cout << "Element at ob[0] is " << ob[0] << endl; 
  cout << "Insert values into ob.\n"; 
  ob.insert(ob.end(), -9999); 
  ob.insert(&ob[1], 99); 
  ob.insert(&ob[-3], -99); 
  for_each(ob.begin(), ob.end(), display); 
  cout << endl; 
  cout << "Element at ob[0] is " << ob[0] << "\n\n"; 
 
  cout << "Insert -7 three times to front of ob.\n"; 
  ob.insert(ob.begin(), 3, -7); 
  for_each(ob.begin(), ob.end(), display); 
  cout << endl; 
  cout << "Element at ob[0] is " << ob[0] << "\n\n"; 
 
  // Use push_back() and pop_back(). 
  cout << "Push back the value 40 onto ob.\n"; 
  ob.push_back(40); 
  for_each(ob.begin(), ob.end(), display); 
  cout << endl; 
  cout << "Pop back two values from ob.\n"; 
  ob.pop_back(); ob.pop_back(); 
  for_each(ob.begin(), ob.end(), display); 
  cout << "\n\n"; 
 
  // Use push_front() and pop_front(). 
  cout << "Push front the value 19 onto ob.\n"; 
  ob.push_front(19); 
  for_each(ob.begin(), ob.end(), display); 
  cout << endl; 
  cout << "Pop front two values from ob.\n"; 
  ob.pop_front(); ob.pop_front(); 
  for_each(ob.begin(), ob.end(), display); 
  cout << "\n\n"; 
 
  // Use front() and back() 
  cout << "ob.front(): " << ob.front() << endl; 
  cout << "ob.back(): " << ob.back() << "\n\n"; 
 
  // Use erase(). 
  cout << "Erase element at 0.\n"; 
  p = ob.erase(&ob[0]); 
  for_each(ob.begin(), ob.end(), display); 
  cout << endl; 
  cout << "Element at ob[0] is " << ob[0] << endl; 
  cout << endl; 
 
  cout << "Erase many elements in ob.\n"; 
  p = ob.erase(&ob[-2], &ob[3]); 
  for_each(ob.begin(), ob.end(), display); 
  cout << endl; 
  cout << "Element at ob[0] is " << ob[0] << endl; 
  cout << endl; 
 
  cout << "Insert ob4 into ob.\n"; 
  RangeArray<int> ob4(0, 2, 0); 
  for(i=0; i < 3; i++) ob4[i] = i+100; 
  ob.insert(&ob[0], ob4.begin(), ob4.end()); 
  for_each(ob.begin(), ob.end(), display); 
  cout << endl; 
  cout << "Element at ob[0] is " << ob[0] << endl; 
  cout << endl; 
 
  cout << "Here is ob shown with its indices:\n"; 
  for(i=ob.getlowerbound(); i<ob.getupperbound(); i++) 
    cout << "[" << i << "]: " << ob[i] << endl; 
  cout << endl; 
 
  // Use the at() function. 
  cout << "Use the at() function.\n"; 
  for(i=ob.getlowerbound(); i < ob.getupperbound(); i++) 
    ob.at(i) = i * 11; 
 
  for(i=ob.getlowerbound(); i < ob.getupperbound(); i++) 
    cout << ob.at(i) << " "; 
  cout << "\n\n"; 
 
  // Use the clear() function. 
  cout << "Clear ob.\n"; 
  ob.clear(); 
  for_each(ob.begin(), ob.end(), display); // no effect! 
  cout << "Size of ob after clear: " << ob.size() 
       << "\nBounds: " << ob.getlowerbound() 
       << " to " << ob.getupperbound() << "\n\n"; 
 
  // Create a copy of an object. 
  cout << "Make a copy of ob2.\n"; 
  RangeArray<int> ob5(ob2); 
  for_each(ob5.begin(), ob5.end(), display); 
  cout << "\n\n"; 
   
  // Construct a new object from a range. 
  cout << "Construct object from a range.\n"; 
  RangeArray<int> ob6(&ob2[-2], ob2.end()); 
  cout << "Size of ob6: " << ob6.size() << endl; 
  for_each(ob6.begin(), ob6.end(), display); 
  cout << endl; 
 
  return 0; 
}

listing 3
// Demonstrate the relational operators. 
#include <iostream> 
#include "ra.h" 
 
using namespace std; 
 
// Display integers -- for use by for_each. 
void display(int v) 
{ 
  cout << v << " "; 
}   
 
int main() 
{ 
  RangeArray<int> ob1(-3, 2, 0), ob2(-3, 2, 0), ob3(-4, 4, 0); 
  int i; 
 
  // Give ob1 and ob2 some values. 
  for(i = -3; i < 3; i++) { 
    ob1[i] = i; 
    ob2[i] = i; 
  } 
   
  cout << "Contents of ob1 and ob2:\n"; 
  for(i=-3; i < 3; i++)  
    cout << ob1[i] << " "; 
  cout << endl; 
 
  for(i=-3; i < 3; i++)  
    cout << ob2[i] << " "; 
  cout << "\n\n"; 
 
  if(ob1 == ob2) cout << "ob1 == ob2\n"; 
  if(ob1 != ob2) cout << "error\n"; 
  cout << endl; 
 
  cout << "Assign ob1[-1] the value 99\n"; 
  ob1[-1] = 99; 
  cout << "Contents of ob1 are now:\n"; 
  for(i=-3; i < 3; i++)  
    cout << ob1[i] << " "; 
  cout << endl; 
 
  if(ob1 == ob2) cout << "error\n"; 
  if(ob1 != ob2) cout << "ob1 != ob2\n"; 
  cout << endl; 
 
  if(ob1 < ob2) cout << "ob1 < ob2\n"; 
  if(ob1 <= ob2) cout << "ob1 <= ob2\n"; 
  if(ob1 > ob2) cout << "ob1 > ob2\n"; 
  if(ob1 >= ob2) cout << "ob1 >= ob2\n"; 
 
  if(ob2 < ob1) cout << "ob2 < ob1\n"; 
  if(ob2 <= ob1) cout << "ob2 <= ob1\n"; 
  if(ob2 > ob1) cout << "ob2 > ob1\n"; 
  if(ob2 >= ob1) cout << "ob2 >= ob1\n"; 
  cout << endl; 
 
  // Compare objects of differing sizes. 
  if(ob3 != ob1) cout << "ob3 != ob1\n"; 
  if(ob3 == ob1) cout << "ob3 == ob1\n"; 
 
  return 0; 
}

listing 4
// Store class objects in a RangeArray. 
#include <iostream> 
#include "ra.h" 
 
using namespace std; 
 
class test { 
public: 
  int a; 
 
  test() { cout << "Constructing\n"; a=0; } 
 
  test(const test &o) { 
    cout << "Copy Constructor\n"; 
    a = o.a; 
  } 
 
  ~test() { cout << "Destructing\n"; } 
}; 
 
int main() 
{ 
  RangeArray<test> t(-3, 1, test()); 
  int i; 
 
  cout << "Original contents of t:\n"; 
  for(i=-3; i < 2; i++) cout << t[i].a << " "; 
  cout << endl; 
 
  // Give t some new values. 
  for(i=-3; i < 2; i++) t[i].a = i; 
 
  cout << "New contents of t:\n"; 
  for(i=-3; i < 2; i++) cout << t[i].a << " "; 
  cout << endl; 
 
  // Copy to new container. 
  RangeArray<test> t2(-7, 3, test()); 
  copy(t.begin(), t.end(), &t2[-2]); 
 
  cout << "Contents of t2:\n"; 
  for(i=-7; i < 4; i++) cout << t2[i].a << " "; 
  cout << endl; 
 
  RangeArray<test> t3(t.begin()+1, t.end()-1); 
  cout << "Contents of t3:\n"; 
  for(i=t3.getlowerbound(); i < t3.getupperbound(); i++)  
    cout << t3[i].a << " "; 
  cout << endl; 
 
  t.clear(); 
 
  cout << "Size after clear(): " << t.size() << endl; 
 
  // Assign container objects. 
  t = t3; 
  cout << "Contents of t:\n"; 
  for(i=t.getlowerbound(); i<t.getupperbound(); i++) 
    cout << t[i].a << " "; 
  cout << endl; 
 
  return 0; 
}