Computer Science Canada

operator overloading
Author:  abcdefghijklmnopqrstuvwxy [ Mon Jul 30, 2007 8:30 pm ]
Post subject:  operator overloading
What's wrong with this?

code:

#include <stdlib.h>

char* operator+(char* one, char* two) {
  strcat(one, two);
  return one;
}

int main() {
  char* one = "You";
  char* two = "Suck";
  printf(one+two);
}
Author:  rizzix [ Tue Jul 31, 2007 1:11 am ]
Post subject:  RE:operator overloading
C does not have operator overloading. I think you're mixing up C with C++.
Author:  abcdefghijklmnopqrstuvwxy [ Tue Jul 31, 2007 2:31 am ]
Post subject:  RE:operator overloading
So what is the easiest way to join two strings without declaring a new variable to hold them?

To me it seems onerous to declare a new variable and use strncat()...
Author:  md [ Tue Jul 31, 2007 9:25 am ]
Post subject:  RE:operator overloading
strcat( string1, string2); just like in your code. However, if you do this with your code you'll get a nice overflow.

C is horrible for strings, they end up just being glorified arrays that use a null character to mark the end. If you use strcat() and the resulting string is longer then the array you are attepting to store it in C really has no way of knowing, so it does as you ask. Which of course leads to all sorts of messy errors.

Creating a new string is unfortunately almost always the only way to be sure that you don't write beyond the length of your original strings.
Author:  wtd [ Tue Jul 31, 2007 3:13 pm ]
Post subject:  RE:operator overloading
The best route is to use a function which allocates and returns a new string. However, beware! If you do this, you will be tempted to use it immediately without assigning the result of that function to a variable.

This way lies madness, as every time you use the function, you allocate memory which must be freed, and without doing so, you have a memory leak. Smile
Author:  OneOffDriveByPoster [ Tue Aug 07, 2007 5:31 pm ]
Post subject:  Re: RE:operator overloading
wtd @ Tue Jul 31, 2007 3:13 pm wrote:
If you do this, you will be tempted to use it immediately without assigning the result of that function to a variable.

wtd, of course you know this, but for the benefit of those who don't:
C:
extern void my_malloc_strcat(char **, char const *, char const *);

:


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