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Language: C++
Expertise: Intermediate
Dec 18, 1998



Building the Right Environment to Support AI, Machine Learning and Deep Learning

Checking a Vector's Capacity

The member function capacity() returns the total number of elements that a vector can hold without requiring reallocation:
#include <iostream>
#include <vector>
using namespace std;

void main() 
 vector <int> vi;
 vi.reserve(10);  //make room for at least 10 more int's
 cout<< vi.size(); //output 0; no elements are stored in vi 
cout<< vi.capacity(); //output 10; vi has enough room for 10 elements
You can use capacity() before inserting new elements to check whether existing iterators may become invalidated as a result.
Danny Kalev
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