chap24.lst

Borland C++ Builder The Complete Reference 例程源代码

listing 3
class three_d { 
public: 
  int x, y, z; // 3-d coordinates 
  three_d(int a, int b, int c) { x=a; y=b; z=c; } 
} ;

listing 4
// Display X, Y, Z coordinates (three_d's inserter). 
ostream &operator<<(ostream &stream, three_d obj) 
{ 
  stream << obj.x << ", "; 
  stream << obj.y << ", "; 
  stream << obj.z << "\n"; 
  return stream; // return the stream 
}

listing 5
#include <iostream> 
using namespace std; 
 
class three_d { 
public: 
  int x, y, z; // 3-d coordinates 
  three_d(int a, int b, int c) { x=a; y=b; z=c; } 
} ; 
 
// Display X, Y, Z coordinates - three_d inserter. 
ostream &operator<<(ostream &stream, three_d obj) 
{ 
  stream << obj.x << ", "; 
  stream << obj.y << ", "; 
  stream << obj.z << "\n"; 
  return stream;  // return the stream 
} 
 
int main() 
{ 
  three_d a(1, 2, 3), b(3, 4, 5), c(5, 6, 7); 
 
  cout << a << b << c; 
 
  return 0; 
}

listing 6
// Limited version - don't use. 
ostream &operator<<(ostream &stream, three_d obj) 
{ 
  cout << obj.x << ", "; 
  cout << obj.y << ", "; 
  cout << obj.z << "\n"; 
  return stream;  // return the stream 
}

listing 7
#include <iostream> 
using namespace std; 
 
class three_d { 
  int x, y, z; // 3-d coordinates - - now private 
public: 
  three_d(int a, int b, int c) { x=a; y=b; z=c; } 
  friend ostream &operator<<(ostream &stream, three_d obj); 
} ; 
 
// Display X, Y, Z coordinates - three_d inserter. 
ostream &operator<<(ostream &stream, three_d obj) 
{ 
  stream << obj.x << ", "; 
  stream << obj.y << ", "; 
  stream << obj.z << "\n"; 
  return stream;  // return the stream 
} 
 
int main() 
{ 
  three_d a(1, 2, 3), b(3, 4, 5), c(5, 6, 7); 
 
  cout << a << b << c; 
 
  return 0; 
}

listing 8
// Get three dimensional values - extractor. 
istream &operator>>(istream &stream, three_d &obj) 
{ 
  cout <<  
    "Enter X Y Z values, separating each with a space: "; 
  stream >> obj.x >> obj.y >> obj.z; 
  return stream; 
}

listing 9
#include <iostream> 
using namespace std; 
 
class three_d { 
  int x, y, z; // 3-d coordinates 
public: 
  three_d(int a, int b, int c) {x=a; y=b; z=c;} 
  friend ostream &operator<<(ostream &stream, three_d obj); 
  friend istream &operator>>(istream &stream, three_d &obj); 
} ; 
 
// Display X, Y, Z coordinates - inserter. 
ostream &operator<<(ostream &stream, three_d obj) 
{ 
  stream << obj.x << ", "; 
  stream << obj.y << ", "; 
  stream << obj.z << "\n"; 
  return stream; // return the stream 
} 
 
// Get three dimensional values - extractor. 
istream &operator>>(istream &stream, three_d &obj) 
{ 
  cout <<  
    "Enter X Y Z values, separating each with a space: "; 
  stream >> obj.x >> obj.y >> obj.z; 
  return stream; 
} 
 
int main() 
{ 
  three_d a(1, 2, 3); 
 
  cout << a; 
  cin >> a; 
  cout << a; 
 
  return 0; 
}

listing 10
stream.setf(ios::showbase);

listing 11
#include <iostream> 
using namespace std; 
 
int main() 
{ 
  cout.setf(ios::showpos); 
  cout.setf(ios::scientific); 
  cout << 123 << " " << 123.23 << " "; 
 
  return 0; 
}

listing 12
cout.setf(ios::scientific | ios::showpos);

listing 13
#include <iostream> 
using namespace std; 
 
void showflags (long f); 
 
int main () 
{ 
  long f; 
 
  f = cout.flags(); 
 
  showflags(f); 
  cout.setf(ios::showpos); 
  cout.setf(ios::scientific); 
 
  f = cout.flags(); 
  showflags(f); 
 
  cout.unsetf(ios::scientific); 
 
  f = cout.flags(); 
  showflags(f); 
 
  return 0; 
} 
 
void showflags(long f) 
{ 
  long i; 
 
  for(i=0x4000; i; i = i >> 1) 
    if(i & f) cout << "1 "; 
    else cout << "0 "; 
 
  cout << "\n"; 
}

listing 14
#include <iostream> 
using namespace std; 
 
int main() 
{ 
  cout.setf(ios::showpos); 
  cout.setf(ios::scientific); 
  cout << 123 << " " << 123.23 << "\n"; 
 
  cout.precision(2); // two digits after decimal point 
  cout.width(10);  // in a field of ten characters 
  cout << 123 << " " << 123.23 << "\n"; 
 
  cout.fill('#');  // fill using # 
  cout.width(10);  // in a field of ten characters 
  cout << 123 << " " << 123.23; 
 
  return 0; 
}

listing 15
#include <iostream> 
#include <iomanip> 
using namespace std; 
 
int main() 
{ 
  cout << setiosflags(ios::fixed); 
  cout << setprecision(2) << 1000.243 << endl; 
  cout << setw(20) << "Hello there."; 
 
  return 0; 
}

listing 16
#include <iostream> 
#include <iomanip> 
using namespace std; 
 
main() 
{ 
  cout << setiosflags(ios::showpos); 
  cout << setiosflags(ios::scientific); 
  cout << 123 << " " << 123.23; 
 
  return 0; 
}

listing 17
#include <iostream> 
using namespace std; 
 
int main() 
{ 
  char s[80]; 
 
  cin >> ws >> s; 
  cout << s; 
}

listing 18
#include <iostream> 
#include <iomanip> 
using namespace std; 
 
ostream &setup(ostream &stream) 
{ 
  stream.setf(ios::left); 
  stream << setw(10) << setfill('$'); 
  return stream; 
} 
 
int main() 
{ 
  cout << 10 << " " << setup << 10; 
 
  return 0; 
}

listing 19
#include <iostream> 
#include <iomanip> 
using namespace std; 
 
istream &prompt(istream &stream) 
{ 
  cin >> hex; 
  cout << "Enter number using hex format: "; 
 
  return stream; 
} 
 
int main() 
{ 
  int i; 
 
  cin >> prompt >> i; 
  cout << i; 
 
  return 0; 
}

listing 20
ifstream in;  // input 
ofstream out; // output 
fstream both; // input and output

listing 21
ofstream out; 
out.open("test", ios::out);

listing 22
out.open("test"); // defaults to output and normal file

listing 23
if(!mystream) { 
  cout << "Cannot open file.\n"; 
  // handle error 
}

listing 24
ifstream mystream("myfile"); // open file for input

listing 25
if(!mystream.is_open()) { 
  cout << "File is not open.\n"; 
  // ...

listing 26
mystream.close();

listing 27
#include <iostream> 
#include <fstream> 
using namespace std; 
 
int main() 
{ 
  ofstream out("test"); 
  if(!out) { 
    cout << "Cannot open file.\n"; 
    return 1; 
    } 
 
  out << 10 << " " << 123.23 << "\n"; 
  out << "This is a short text file.\n"; 
 
  out.close(); 
 
  return 0; 
}

listing 28
#include <iostream> 
#include <fstream> 
using namespace std; 
 
int main() 
{ 
  int i; 
  float f; 
  char str[80]; 
 
  ifstream in("test"); 
  if(!in) { 
    cout << "Cannot open file.\n"; 
    return 1; 
  } 
 
  in >> i; 
  in >> f; 
  in >> str; 
 
  cout << i << " " << f << " " << "\n"; 
  cout << str; 
 
  in.close(); 
  return 0; 
}

listing 29
#include <iostream> 
#include <fstream> 
using namespace std; 
 
int main(int argc, char *argv[]) 
{ 
  char ch; 
 
  if(argc!=2) { 
    cout << "Usage: PR <filename>\n"; 
    return 1; 
  } 
 
  ifstream in(argv[1], ios::in | ios::binary); 
  if(!in) { 
    cout << "Cannot open file.\n"; 
    return 1; 
  } 
 
  while(in) { // in will be null when eof is reached 
    in.get(ch); 
    cout << ch; 
  } 
  in.close(); 
 
  return 0; 
}

listing 30
while(in.get(ch)) 
  cout << ch;

listing 31
#include <iostream> 
#include <fstream> 
using namespace std; 
 
int main() 
{ 
  char *p = "hello there\n\r\xfe\xff"; 
 
  ofstream out("test", ios::out | ios::binary); 
  if(!out) { 
    cout << "Cannot open file.\n"; 
    return 1; 
   } 
 
  while(*p) out.put(*p++); 
  out.close(); 
 
  return 0; 
}

listing 32
#include <iostream> 
#include <fstream> 
using namespace std; 
 
int main() 
{ 
  int n[5] = {1, 2, 3, 4, 5}; 
  register int i; 
 
  ofstream out("test", ios::out | ios::binary); 
  if(!out) { 
    cout << "Cannot open file.\n"; 
    return 1; 
   } 
 
  out.write((char *) &n, sizeof n); 
  out.close(); 
 
  for(i=0; i<5; i++) // clear array 
    n[i] = 0; 
 
  ifstream in("test", ios::in | ios::binary); 
  in.read((char *) &n, sizeof n); 
 
  for(i=0; i<5; i++) // show values read from file 
    cout << n[i] << " "; 
  in.close(); 
 
  return 0; 
}

listing 33
#include <iostream> 
#include <fstream> 
#include <cstdlib> 
using namespace std; 
 
int main(int argc, char *argv[]) 
{ 
  if(argc!=3) { 
    cout << "Usage: CHANGE <filename> <byte>\n"; 
    return 1; 
  } 
 
  fstream out(argv[1], ios::in | ios::out | ios::binary); 
  if(!out) { 
    cout << "Cannot open file.\n"; 
    return 1; 
  } 
 
  out.seekp(atoi(argv[2]), ios::beg); 
 
  out.put('X'); 
  out.close(); 
 
  return 0; 
}

listing 34
#include <iostream> 
#include <fstream> 
#include <cstdlib> 
using namespace std; 
 
int main(int argc, char *argv[]) 
{ 
  char ch; 
 
  if(argc!=3) { 
    cout << "Usage: NAME <filename> <starting location>\n"; 
    return 1; 
  } 
 
  ifstream in(argv[1], ios::in | ios::binary); 
  if(!in) { 
    cout << "Cannot open file.\n"; 
    return 1; 
  } 
 
  in.seekg(atoi(argv[2]), ios::beg); 
 
  while(in.get(ch)) 
    cout << ch; 
 
  in.close(); 
 
  return 0; 
}