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The CICA Windows Explosion!
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eckelt01.zip
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10
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UNARY.CPP
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C/C++ Source or Header
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1995-02-23
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5KB
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195 lines
// File from page 401 in "Thinking in C++" by Bruce Eckel
//////////////////////////////////////////////////
// From the compressed package ECKELT01.ZIP 2/21/95
// Copyright (c) Bruce Eckel, 1995
// Source code file from the book "Thinking in C++",
// Prentice Hall, 1995, ISBN: 0-13-917709-4
// All rights reserved EXCEPT as allowed by the following
// statements: You may freely use this file for your own
// work, including modifications and distribution in
// executable form only. You may copy and distribute this
// file, as long as it is only distributed in the complete
// (compressed) package with the other files from this
// book and you do not remove this copyright and notice.
// You may not distribute modified versions of the source
// code in this package. This package may be freely placed
// on bulletin boards, internet nodes, shareware disks and
// product vendor disks. You may not use this file in
// printed media without the express permission of the
// author. Bruce Eckel makes no
// representation about the suitability of this software
// for any purpose. It is provided "as is" without express
// or implied warranty of any kind. The entire risk as to
// the quality and performance of the software is with
// you. Should the software prove defective, you assume
// the cost of all necessary servicing, repair, or
// correction.
// If you think you've found an error, please
// email all modified files with loudly commented changes
// to: eckel@aol.com (please use the same
// address for non-code errors found in the book).
//////////////////////////////////////////////////
//: UNARY.CPP -- Overloading unary operators
#include <iostream.h>
class integer {
long i;
public:
integer(long I = 0) : i(I) {}
// No side effects takes const& argument:
friend const integer&
operator+(const integer& a);
friend const integer
operator-(const integer& a);
friend const integer
operator~(const integer& a);
friend integer*
operator&(integer& a);
friend int
operator!(const integer& a);
// Side effects don't take const& argument:
// Prefix:
friend const integer&
operator++(integer& a);
// Postfix:
friend const integer
operator++(integer& a, int);
// Prefix:
friend const integer&
operator--(integer& a);
// Postfix:
friend const integer
operator--(integer& a, int);
};
// Global operators:
const integer& operator+(const integer& a) {
cout << "+integer\n";
return a; // Unary + has no effect
}
const integer operator-(const integer& a) {
cout << "-integer\n";
return integer(-a.i);
}
const integer operator~(const integer& a) {
cout << "~integer\n";
return integer(~a.i);
}
integer* operator&(integer& a) {
cout << "&integer\n";
return &a;
}
int operator!(const integer& a) {
cout << "!integer\n";
return !a.i;
}
// Prefix; return incremented value
const integer& operator++(integer& a) {
cout << "++integer\n";
a.i++;
return a;
}
// Postfix; return the value before increment:
const integer operator++(integer& a, int) {
cout << "integer++\n";
integer r(a.i);
a.i++;
return r;
}
// Prefix; return decremented value
const integer& operator--(integer& a) {
cout << "--integer\n";
a.i--;
return a;
}
// Postfix; return the value before decrement:
const integer operator--(integer& a, int) {
cout << "integer--\n";
integer r(a.i);
a.i--;
return r;
}
void f(integer a) {
+a;
-a;
~a;
integer* ip = &a;
!a;
++a;
a++;
--a;
a--;
}
// Member operators (implicit "this"):
class byte {
unsigned char b;
public:
byte(unsigned char B = 0) : b(B) {}
// No side effects: const member function:
const byte& operator+() const {
cout << "+byte\n";
return *this;
}
const byte operator-() const {
cout << "-byte\n";
return byte(-b);
}
const byte operator~() const {
cout << "~byte\n";
return byte(~b);
}
byte operator!() const {
cout << "!byte\n";
return byte(!b);
}
byte* operator&() {
cout << "&byte\n";
return this;
}
// Side effects: non-const member function:
const byte& operator++() { // Prefix
cout << "++byte\n";
b++;
return *this;
}
const byte operator++(int) { // Postfix
cout << "byte++\n";
byte(b);
b++;
return b;
}
const byte& operator--() { // Prefix
cout << "--byte\n";
--b;
return *this;
}
const byte operator--(int) { // Postfix
cout << "byte--\n";
byte(b);
--b;
return b;
}
};
void g(byte b) {
+b;
-b;
~b;
byte* bp = &b;
!b;
++b;
b++;
--b;
b--;
}
main() {
integer a;
f(a);
byte b;
g(b);
}