Question about an BYTE value changing into pointer, then array

[yeah1000]

Hi, i am in trouble with the following: //function declarations// void function1(); void function2(BYTE *temp); //functions// void function1(){ BYTE temp; function2(&temp); } void function2(BYTE *temp){ int i; for(i=0;i<10;i++){ temp[i] = 1; } } How come temp can be used as an array in function2 ? function2 requires a pointer to BYTE value not a BYTE array... TY

[Chris Losinger]

yeah1000 wrote:

function2 requires a pointer to BYTE value not a BYTE array...

in C/C++, there is no (syntactical) difference between a pointer to a single variable and a pointer to the start of an array.

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[Nemanja Trifunovic]

The problem here is function2(); it is declared to take a pointer to BYTE and then assumes this pointer points to the first element of a BYTE[10] array. It is unfortunate that it compiles at all, but it has to because in C the name of array will automatically decay to the type of pointer to its first element[^].

utf8-cpp

[CPallini]

Nemanja Trifunovic wrote:

It is unfortunate that it compiles at all

I don't think so. :)

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[Nemanja Trifunovic]

CPallini wrote:

I don't think so

Care to explain? [edit] Never mind - my remark would make sense if his second function was declared to have an array as parameter - somehow I thought it was :) [/edit]

utf8-cpp

modified on Tuesday, November 24, 2009 2:24 PM

[Iain Clarke Warrior Programmer]

Well, which is cleaner? 1)

for (i = 0; i < 7; i++)
DoSomething (ptr [i]);

for (i = 0; i < 7; i++)
DoSomething (*(ptr+i));

for (i = 0; i < 7; i++)
DoSomething (*ptr++)

1 & 2 do the same thing. 3 messes up ptr too. Iain.

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[Nemanja Trifunovic]

That's fine, but I don't see what it has to do with my observation that array decay was an unfortunate decision by creators of C. If it wasn't for that, you could declare a function to accept either an array or a pointer, but it would be a compile error if you passed a pointer when an array is expected (look at OP). [edit] Now that *I* looked at OP carefully, I see that my remark does not make sense. Somehow, I thought his second function was declared to take an array, and it really takes a pointer. [/edit]

utf8-cpp

modified on Tuesday, November 24, 2009 2:25 PM

[David Crow]

See here.

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