Re: pointers to functions

From:
"Allan W" <allan_w@my-dejanews.com>
Newsgroups:
comp.lang.c++.moderated
Date:
10 May 2006 08:46:28 -0400
Message-ID:
<1147219962.892129.221560@y43g2000cwc.googlegroups.com>
BigBrian wrote:

What about something like this....

#include <iostream>
//yuck! using namespace std;

int addition (int a, int b)
{ return (a+b); }

int subtraction (int a, int b)
{ return (a-b); }

//int minus (int,int) = subtraction;

typedef int(op)(int,int);


BigBrian was the first person to suggest using a typedef!
A great idea (if the OP's training has already covered this
concept, which unfortunately we don't know), but he didn't
complete the thought...

op * minus = subtraction;


Good, but...

int operation (int x, int y, int (*functocall)(int,int))


This should be

int operation (int x, int y, op*functocall)

{
    int g;
    g = (*functocall)(x,y);


And this would be a lot easier to read as
     g = functocall(x,y);

    return (g);
}


Or better yet, as someone already pointed out:

   int operation(int x, int y, op*func) { return func(x,y); }

int main ()
{
    int m,n;

    m = operation (7, 5, addition);
    n = operation (20, m, minus);
    std::cout <<n;
    return 0;
}


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