» CS 330 Lecture 21

CS 330 Lecture 21 – First C++

March 26, 2012 by Chris Johnson. Filed under cs330, lectures, spring 2012.

Agenda

what do you know about C++?
C++ roots: Simula
Bjarne Strostroup
TIOBE index for C++
values vs. pointers vs. references (which?)
classes in C++

mapping between C with Classes and C
can be made on stack
for heap, why new/delete? (RAII)
access control
constructor/deconstructor
use initialization lists
default constructor
copy constructor

an example class: FasterString
Bjarne’s goal in C++: type parity

custom classes on stack or heap, unlike Simula
can overload builtin operators to work with classes

TODO

Have a peek through the C++ FAQ.

Code

FasterString.cpp

class FasterString {
  public:
    FasterString();
    FasterString(const char *src);

    const char *GetCString();

  private:
    char *characters;
    int length;
};

FasterString::FasterString() :
  characters(NULL),
  length(0) {
}

FasterString::FasterString(const char *src) :
  length(strlen(src)),
  characters(NULL) {
  /* characters = malloc(sizeof(char) * length); */
  characters = new char[length];
  memcpy(characters, src, length * sizeof(char));
}

const char *FasterString::GetCString() {
  return characters;  
}

int main() {
  FasterString f("hi, jeff");
  // ctor has already been called, and f is valid
  std::cout << "f.GetCString(): " << f.GetCString() << std::endl;
  return 0;
}

Haiku

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