Vector Elements

[Brett Irving]

Hi people, was curious if there was a way to change all the elements
in a vector without having to loop through and access every one and
then change them.

for example. I have a vector that is 10 000 elements, and one value
that I want to copy them all to. Can I do it without looping?

Any advice is appreciated.

 

[John Harrison]

Hi people, was curious if there was a way to change all the elements
in a vector without having to loop through and access every one and
then change them.

for example. I have a vector that is 10 000 elements, and one value
that I want to copy them all to. Can I do it without looping?

Any advice is appreciated.

Of course

vec.assign(vec.size( ), some_value);

Suggest you familiarise yourself with some standard library documentation.
This site is good, http://www.dinkumware.com/refxcpp.html

john

 

[Ron Natalie]

Hi people, was curious if there was a way to change all the elements
in a vector without having to loop through and access every one and
then change them.

erase them all and the resize them with the new value as fill. There
is an oft-forgotten defaulted argument to the vector constructor and
resize function that specifies what the

vector<int> foo(10000); // 10000 elements of zero.
foo.clear();
foo.resize(10000, 5); // 10000 elements of 5;

Of course, the other way is to use fill
fill(foo.begin(), foo.end(), 5);

 

[Catalin Pitis]

erase them all and the resize them with the new value as fill. There
is an oft-forgotten defaulted argument to the vector constructor and
resize function that specifies what the

vector<int> foo(10000); // 10000 elements of zero.
foo.clear();
foo.resize(10000, 5); // 10000 elements of 5;

Of course, the other way is to use fill
fill(foo.begin(), foo.end(), 5);

I think using fill is much better approach in this case, from performance
point of view. I don't know if resizing implies reallocation of memory even
for new size smaller than or equal to the old one.

br,
Catalin