[Okta Webinar] Learn how to a build a cloud-first strategyRegister Now

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 266
  • Last Modified:

Loop Question

Instead of using to for loops to initialize a 2D array is there another way to initialize a 2D array?
0
Andy36
Asked:
Andy36
  • 5
  • 3
  • 2
  • +8
1 Solution
 
jhanceCommented:
initializers.

For example:

int x[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,};
0
 
thienpnguyenCommented:
Same as jhance 's comment, here is other example for array 2D


int Arr[2][3] =
{
   { 3 , 5, 7 },
   { 1, 10, 20 }
};

 
0
 
Andy36Author Commented:
I mean is there a different way you can initialize a 2d array with some other kind of loop like a while or do while?
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
Andy36Author Commented:
I mean is there a different way you can initialize a 2d array with some other kind of loop like a while or do while?
0
 
jhanceCommented:
Just what _ARE_ you asking?  Loops are loops.  

for, do, while, etc. are all pretty much different words for the same thing.  You really have 3 choices:

1) A loop.
2) An initializer.
3) Straight line code.

Perhaps a better question would help as this one coupled with your comment is very confusing.
0
 
yonatCommented:
In some cases you can use memset(). Or is this homework?
0
 
TriskelionCommented:
You can use memset like yonat said and/or you can make the array static which will initialize it to all zero values.

static int Arr[2][3];
0
 
Andy36Author Commented:
I Have already initrialized a 2d array like this:

     for(int i = 0; i < n; i++)
          for(int j=0; j<n; j++) Magic[i][j] = 0;
          Magic[0][(n-1)/2]=1;//Middle of first row
                         //(i,j) is the current position.

How could I initialize it with a different loop? Or is it not possible?
0
 
Andy36Author Commented:
What is memset()? The homework is already done with the for loops. I just wanted to see if I could write it with a different loop.
0
 
MFCRichCommented:
memset(Magic, 0, sizeof(Magic));

This will fill it with NULL bytes
0
 
wendersonCommented:
You can also, initialize the first element with an arbitrary value, so, all the others will initialized to zero, ex.:

int array[10][10] = { 1 };

Wenderson
0
 
abelCommented:
If you really want to use a while-loop, you'll do the counting in it:

int i = 0;
while(i < 10)
{
    i++;
    //do inits
}

which is the same as:

for(int i=0; i<10; i++)
{
    //do inits
}


Cheers,
Abel
0
 
griesshCommented:
void main()
{
  int i,j;
  int arr[4,4];
  // FOR loop
  for (i=0; i< 3; i++) {
    for (j=0; j<3; j++) {
      arr[i,j] = i+j;
    }
  }
  // do - while loop
  i = 0;
  j = 0;
  do {
    do {
      arr[i,j] = i+j;
      i++;
    }
    while (j<3);
    j++;
  }
  while (i<3);

  // while loop
  i=0;
  j=0;
  while (i<3) {
    while (j<3) {
      arr[i,j] = i+j;
      i++;
    }
    j++;
  }

  // Mix
  i=0;
  while (i<3) {
    for (j=0; j<3; j++) {
      arr[i,j] = i+j;
    }
    j++;
  }
}


======
Werner
0
 
rtenhoveCommented:
For an N x N identity matrix, you could initialize it like so:

int m[N][N];

memset(m, 0, sizeof m );

for (int i = 0; i < N; i++)
    m[i][i] = 1;
You could also initialize the matrix from a file, assuming that you serialized the contents of the matrix previously.

You're probably looking for static initialization.

int m[2][3] = {{1,2,3},{4,5,6}};Alternatively, you could do it in a single loop:

int m[M][N];
int *pm = &(m[0][0]);

for (int i = 0; i < M * N; i++ )
    pm[i] = i;


0
 
Andy36Author Commented:
Griessh

What is int arr[4,4];
 
Is this a 2d array? I thought all 2d arrays went like arr[4][4];
0
 
griesshCommented:
Sorry, typo! Should be [4][4] ... <shame on me>

======
Werner
0
 
griesshCommented:
Dear Andy36

I think you forgot this question. I will ask Community Support to close it unless you finalize it within 7 days. You can always request to keep this question open. But remember, experts can only help you if you provide feedback to their questions.
Unless there is objection or further activity,  I will suggest to accept

     "jhance"

comment(s) as an answer.

If you think your question was not answered at all, you can post a request in Community support (please include this link) to refund your points. The link to the Community Support area is: http://www.experts-exchange.com/commspt/

PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!
======
Werner
0
 
MindphaserCommented:
Force accepted

** Mindphaser - Community Support Moderator **
0

Featured Post

Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

  • 5
  • 3
  • 2
  • +8
Tackle projects and never again get stuck behind a technical roadblock.
Join Now