I want to reuse a std::vector
within a for loop. However, I need the vector to be empty for each iteration step of the for loop.
Question: How can I empty a vector rapidly without changing its capacity in the most efficient way?
What I used so far is
std::vector<int> myVec;
for(int i=0; i<A_BIG_NUMBER; ++i) {
std::vector<T>().swap(myVec);
myVec.reserve(STANDARD_MAXIMUM);
/// .. doing business
}
Cheers!
Solution:
Thanks for the answers, here is how I implemented (checked) it:
#include <vector>
#include <iostream>
int main() {
int n = 10;
std::vector< int > myVec;
myVec.reserve(n);
for(int j=0; j<3; ++j) {
myVec.clear();
for(int i=0; i<n; ++i) {
myVec.push_back(i);
}
for(int i=0; i<myVec.size(); ++i) {
std::cout << i << ": " << myVec[i] << std::endl;
}
}
return 0;
}
EDIT: changed from operator[]
to push_back
.
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