vector<doublev1 (5,1);
vector<doublev2 ;
v2 = v1; // 1
v2.assign(v1.be gin(),v1.end()) ; // 2
Are 1 and 2 the same, or are their subtle differences between them.
Which is preferable, if either? And yes, I know I could use the
construction vector<doublev2 (v1), but I'm giving an example above.
Thank you c++ users. 4 6917
Chris Roth wrote:
vector<doublev1 (5,1);
vector<doublev2 ;
v2 = v1; // 1
v2.assign(v1.be gin(),v1.end()) ; // 2
Are 1 and 2 the same, or are their subtle differences between them.
Which is preferable, if either? And yes, I know I could use the
construction vector<doublev2 (v1), but I'm giving an example above.
Thank you c++ users.
No observable difference between them, but 1 is clearly better since it
is clearer to any reader of the code. With 2 you have to check the
arguments to understand the meaning.
john
Chris Roth wrote:
vector<doublev1 (5,1);
vector<doublev2 ;
v2 = v1; // 1
v2.assign(v1.be gin(),v1.end()) ; // 2
Are 1 and 2 the same, or are their subtle differences between them.
Which is preferable, if either? And yes, I know I could use the
construction vector<doublev2 (v1), but I'm giving an example above.
As John said, there's probably no detectable difference. The latter
construct (assign) is more useful when you want to copy a subvector.
e.g.:
vector<doublev1 ;
vector<doublev2 ;
// fill v1 here.
vector<double>: :iterator start_iter = some_iterator_i nto_v1;
vector<double>: :iterator end_iter = some_other_iter ator_into_v1;
v2.assign(start _iter, end_iter);
On Feb 21, 4:40 pm, red floyd <no.s...@here.d udewrote:
Chris Roth wrote:
vector<doublev1 (5,1);
vector<doublev2 ;
v2 = v1; // 1
v2.assign(v1.be gin(),v1.end()) ; // 2
Are 1 and 2 the same, or are their subtle differences between them.
Which is preferable, if either? And yes, I know I could use the
construction vector<doublev2 (v1), but I'm giving an example above.
As John said, there's probably no detectable difference. The latter
construct (assign) is more useful when you want to copy a subvector.
e.g.:
vector<doublev1 ;
vector<doublev2 ;
// fill v1 here.
vector<double>: :iterator start_iter = some_iterator_i nto_v1;
vector<double>: :iterator end_iter = some_other_iter ator_into_v1;
v2.assign(start _iter, end_iter);
Also, using assign allows you to assign across container types:
vector<intv;
list<intll;
// fill ll here
v.assign(ll.beg in(), ll.end());
red floyd wrote:
Chris Roth wrote:
>vector<doublev 1(5,1); vector<doublev 2;
v2 = v1; // 1 v2.assign(v1.b egin(),v1.end() ); // 2
Are 1 and 2 the same, or are their subtle differences between them. Which is preferable, if either? And yes, I know I could use the construction vector<doublev2 (v1), but I'm giving an example above.
As John said, there's probably no detectable difference. The latter
construct (assign) is more useful when you want to copy a subvector.
In case 1, v1 must be a vector.
In case 2, v1 can be anything provided that the iterators returned
are of a type that's insertable into v2. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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