CODEWITHSUNDEEP
c++
pyCthon
pyCthon

Reputation: 12341

dynamically changing name of an array in c++

Hi I have a problem where at compile time, I don't know how many vectors in my program are needed. The number required depends on a data set given at run-time, which will results in the range of vectors needed to be from 1 to N.

So if the data set requires ten vectors, it will create vec1,vec2,......vecN

How can i dynamically create the vectors so that they all have a different name?

I would then need to call each array separately. Presumably I could just use strings and a few loops for this.

Upvotes: 1

Views: 1762

Answers (3)

SingerOfTheFall
SingerOfTheFall

Reputation: 29966

You can't do that directly. However, you could use a map to store a vector name, and the vector itself:

map<string, vector<int> > myMap;

You can add elements simply like this (if the element with such key doesn't exist yet):

vector<int> vec;
myMap["vec"] = vec;

If you'll do it with a key that already exists, the value will be replaced. For example:

vector<int> vec;
vector<int> vec1;
myMap["vec"] = vec;
myMap["vec"] = vec1;//now myMap["vec"] holds the vec1 vector

You can also easlly access elements like this:

myMap["vec"]//this will access the vector with the key "vec1"

Upvotes: 5

Some programmer dude
Some programmer dude

Reputation: 409196

You can create a vector to contain your vectors:

std::vector<std::vector<int>> my_vector_of_vectors;

// Add a vector
my_vector_of_vectors.push_back(std::vector<int>{});

// Add a number to the inner vector
my_vector_of_vectors[0].push_back(1);

Upvotes: 5

gbjbaanb
gbjbaanb

Reputation: 52679

you have a vector of vectors, vec[0] to vec[n], each one containing the vector.

However, this works est if you know the number of vectors (eg 10). If you need to add new ones on-demand, then a list of vectors or a map might be a better option for you.

Upvotes: 0

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