Programming Forums > Application Development > C++

kurt · Apr 15th, 2008, 10:55 PM

This is embarrasing, but I've always thought:

int variable[10] = {9};

will init all items to 9. But it does not.

Any cool way to init to a non-zero value besides a for-loop?

Thanks in advance.

mbd · Apr 15th, 2008, 11:16 PM

 c++ Syntax (Toggle Plain Text) 
#include <algorithm>
 
...
 
int variable[10];
std::fill_n(variable, 10, 9);
#include <algorithm>

...

int variable[10];
std::fill_n(variable, 10, 9);

still just a loop under the hood

OpenLoop · Apr 16th, 2008, 6:57 AM

For smaller arrays, you can do this

 c++ Syntax (Toggle Plain Text) 
int variable[5] = {9,9,9,9,9};
int variable[5] = {9,9,9,9,9};

lectricpharaoh · Apr 16th, 2008, 3:48 PM

Quote:

Originally Posted by kurt

This is embarrasing, but I've always thought:

int variable[10] = {9};

will init all items to 9. But it does not.

When you initialize an array like that, it will initialize all elements you specify to the values you give, and any remaining elements will be initialized to zero (for fundamental types) or with the default constructor (for objects). If the array does not have a subscript, then the number of elements is taken from the number of values you provide:

 C++ Syntax (Toggle Plain Text) 
// all set to 9
int array1[10] = {9, 9, 9, 9, 9, 9, 9, 9, 9, 9};
 
// first three set to 9, rest set to 0
int array2[10] = {9, 9, 9};
 
// five elements, all set to 9
int array3[] = {9, 9, 9, 9, 9};
// all set to 9
int array1[10] = {9, 9, 9, 9, 9, 9, 9, 9, 9, 9};

// first three set to 9, rest set to 0
int array2[10] = {9, 9, 9};

// five elements, all set to 9
int array3[] = {9, 9, 9, 9, 9};

Klarre · Apr 16th, 2008, 3:51 PM

memset is a function that can be pretty handy sometimes. Even thought it may not function as expected with your "int" it is good to know about it when you are using char's.
http://www.cplusplus.com/reference/c...ng/memset.html

Apr 15th, 2008, 10:55 PM	#1
kurt Programmer Join Date: Oct 2005 Posts: 68 Rep Power: 3	Init array with a non-zero value This is embarrasing, but I've always thought: int variable[10] = {9}; will init all items to 9. But it does not. Any cool way to init to a non-zero value besides a for-loop? Thanks in advance.

Apr 15th, 2008, 11:16 PM	#2
mbd Programmer Join Date: Nov 2007 Posts: 86 Rep Power: 1	Re: Init array with a non-zero value c++ Syntax (Toggle Plain Text) #include <algorithm> ... int variable[10]; std::fill_n(variable, 10, 9); #include <algorithm> ... int variable[10]; std::fill_n(variable, 10, 9); still just a loop under the hood

Apr 16th, 2008, 6:57 AM	#3
OpenLoop Expert Programmer Join Date: May 2005 Location: East Lansing, MI Posts: 663 Rep Power: 4	Re: Init array with a non-zero value For smaller arrays, you can do this c++ Syntax (Toggle Plain Text) int variable[5] = {9,9,9,9,9}; int variable[5] = {9,9,9,9,9};

Apr 16th, 2008, 3:51 PM	#5
Klarre Game engine designer Join Date: May 2005 Location: Sweden Posts: 301 Rep Power: 4	Re: Init array with a non-zero value memset is a function that can be pretty handy sometimes. Even thought it may not function as expected with your "int" it is good to know about it when you are using char's. http://www.cplusplus.com/reference/c...ng/memset.html __________________ http://www.klarre.se

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Programming Forums > Application Development > C++

Init array with a non-zero value