the following codes pushed back an std::array to a std::vector N times. Is there a more elegant and shorter way of doing this?
#include <iostream>
#include <vector>
#include <array>
#include <iomanip>
#include <complex>
#include <cmath>
int main () {
int N=10;
std::vector< std::array<std::complex<double>,3> > v;
v.reserve(N);
for(int i=0;i<N;i++){
std::array<std::complex<double>,3> el { {0.0,3.0,0.0} };
v.push_back(el);
}
}
Yes but you have to use parentheses when constructing vector
std::vector< std::array<std::complex<double>,3> > v(n, {0.0,3.0,0.0});
If braces are used than initialization list is preferred and in this case you could have unexpected errors.
You can use the std::vector::insert
(#3 in the overload set) member function:
int N=10;
std::vector< std::array<std::complex<double>,3> > v;
v.reserve(N);
v.insert(v.end(), N, { {0.0,3.0,0.0} });
Note that @MarekR's answer is preferable for initializing the vector, as it circumvents the call to reserve
, and setting up an object during initialization is usually better than subsequent member function calls. The above call to std::vector::insert
instead is suitable for adding additional elements later on.
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