Using while / do-while loops for array element setting

Question

I'm having some trouble understanding how to use a while loop to get the same results as this for loop:

for (int i=0; i<N; i++){
    int datum[i] = 0;
}

Basically, to set all the elements in the array datum[N] to 0. Does the following code make sense in that regard, or am I missing something? thanks

int i = 0;
while (i < N){
    datum[i] = 0;
    i++;
}

No you're not :) But for the first loop, why `int`? You can't redeclare `datum[i]`. — Rakete1111, May 21 '16 at 14:25
Initialize them to zero with `int datum[N] = {0};` would be better practice generally. — Scott Stainton, May 21 '16 at 14:27
@ScottStainton: [`int datum[N] = {}` makes more logical sense](http://stackoverflow.com/q/14797810/560648) in C++. — Lightness Races in Orbit, May 21 '16 at 14:38

score 3 · Accepted Answer · answered May 21 '16 at 14:36

3

These two code examples produce the same results.

int i = 0;
while (i < N)
{
     datum[i] = 0;
     i++;
}

for (int i=0; i<N; i++) 
{
   datum[i] = 0; // remove int because you will be redclaring datum
}

answered May 21 '16 at 14:36

sebenalern

score 2 · Answer 2 · answered May 21 '16 at 14:39

2

Don't use either of them. When you declare datum, do so like this:

std::vector<int> datum(N);

Done.

answered May 21 '16 at 14:39

2 Answers2