Can't return array from a function, right?
April 12, 2002 08:13 PM
Let me get this straight, you can''t return an array from a function, correct? You could return a single element from an array, but not the entire array, right? The only way to access an array from a function is by pointers or references is what I''m thinking.
Rhino2876
122
April 12, 2002 08:17 PM
that''s correct.
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To the vast majority of mankind, nothing is more agreeable than to escape the need for mental exertion... To most people, nothing is more troublesome than the effort of thinking.
To the vast majority of mankind, nothing is more agreeable than to escape the need for mental exertion... To most people, nothing is more troublesome than the effort of thinking.
2,123
April 12, 2002 08:24 PM
In C++ you can return a vector:
[ GDNet Start Here | GDNet Search Tool | GDNet FAQ | MS RTFM [MSDN] | SGI STL Docs | Google! | Asking Smart Questions ]
Thanks to Kylotan for the idea!
template < typename T >std::vector< T > Pack( T & data1, T & data2 ){ std::vector< T > v; v.push_back( data1 ); v.push_back( data2 ); return v;} [ GDNet Start Here | GDNet Search Tool | GDNet FAQ | MS RTFM [MSDN] | SGI STL Docs | Google! | Asking Smart Questions ]
Thanks to Kylotan for the idea!
122
April 12, 2002 11:30 PM
Sure you can return an array from a function. An array is just a pointer to memory (address), so your function must return a pointer to a memory location.
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[edited by - aNonamuss on April 12, 2002 12:55:18 AM]
void main(void){ char szTempString[MAX_CHARS]; strcpy(szTempString, ChangeArray());}char *ChangeArray(void){ return "You can return an Array from a Function";} ------
If I'm incorrect, sue me, you'll get nothing
[edited by - aNonamuss on April 12, 2002 12:55:18 AM]
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929
April 13, 2002 04:58 AM
quote: Original post by aNonamuss
Sure you can return an array from a function. An array is just a pointer to memory (address), so your function must return a pointer to a memory location.
Sure, the problem comes when you do something like this:
char *function(){ char buffer[256]; // ... // ... do something with buffer, fill it with what you want // ... return buffer;}int main(){ char *ptr_to_buffer = function(); cout<<ptr_to_buffer[0]; // SHIT!!! "buffer" was destroyed! Ah well, lets just let the program crash return 0;} You get the idea...
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124
April 13, 2002 05:08 AM
Actually just the permission to WRITE to that memory was removed, you can still read its contents just fine.
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"When I have a problem on an Nvidia, I assume that it is my fault. With anyone else''s drivers, I assume it is their fault" - John Carmack
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"When I have a problem on an Nvidia, I assume that it is my fault. With anyone else''s drivers, I assume it is their fault" - John Carmack
-----------------------"When I have a problem on an Nvidia, I assume that it is my fault. With anyone else's drivers, I assume it is their fault" - John Carmack
504
April 13, 2002 05:11 AM
quote: Original post by aNonamuss
Sure you can return an array from a function.
No you can''t.
quote:
An array is just a pointer to memory (address)
No it''s not.
quote:
so your function must return a pointer to a memory location.
You can do that, but a pointer isn''t an array.
April 13, 2002 05:25 AM
"Let me get this straight, you can''t return an array from a function, correct? You could return a single element from an array, but not the entire array, right? The only way to access an array from a function is by pointers or references is what I''m thinking.''
Guys, I already acknowledged that you could use pointers to change an array. I guess what you are all telling me is that I could return the entire array with pointers. That''s cool. Well, why does this work then.
Here is something interesting that I experimented with. A function could change an array without pointers.
CONSOLE OUTPUT:
1
Hi
Press any key to continue
Notice that I actually changed the first 2 elements of c[] with the i[] array that is local to the function test. I thought that local variable do not change values in main unless if you use pointers. Strange.
Guys, I already acknowledged that you could use pointers to change an array. I guess what you are all telling me is that I could return the entire array with pointers. That''s cool. Well, why does this work then.
Here is something interesting that I experimented with. A function could change an array without pointers.
#include int test(char i[]);int main(){ char c[5] = " "; printf("\n\n%d\n\n", test(c)); printf("\n\n%s\n\n", c); return 0;}int test(char i[]){ i[0] = ''H''; i[1] = ''i''; return 1; } CONSOLE OUTPUT:
1
Hi
Press any key to continue
Notice that I actually changed the first 2 elements of c[] with the i[] array that is local to the function test. I thought that local variable do not change values in main unless if you use pointers. Strange.
Rhino2876
208
April 13, 2002 05:30 AM
You''re not passing an array out of a function there, you''re passing one in.
Helpful links:
How To Ask Questions The Smart Way | Google can help with your question | Search MSDN for help with standard C or Windows functions
Helpful links:
How To Ask Questions The Smart Way | Google can help with your question | Search MSDN for help with standard C or Windows functions
April 13, 2002 05:38 AM
from Mr. Obvious:
"You''re not passing an array out of a function there, you''re passing one in."
I know that. But why is the function changing the array in main? It should only change the array in the function, not the array in main. I thought that''s how local variable worked.
"You''re not passing an array out of a function there, you''re passing one in."
I know that. But why is the function changing the array in main? It should only change the array in the function, not the array in main. I thought that''s how local variable worked.
Rhino2876
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