Question

How to optimize the creation of a vector of classes in C++

Answer 1

#include <iostream>
#include <vector>

class Vertex {
public:
    float x, y, z;
    
    Vertex(float x, float y, float z) : x(x), y(y), z(z) {}
    
    Vertex (const Vertex& vertex) : x(vertex.x), y(vertex.y), z(vertex.z) {
        std::cout << "copy vertex" << "\n";
    }
};
    
int main() {
    std::vector<Vertex> ve;
    
    ve.reserve(3); // Set capacity
    
    // Nothing is consructed in main()
    
    ve.emplace_back(3, 7, 0); 
    ve.emplace_back(2, 1, 0);
    ve.emplace_back(8, 9, 6);
}



/*
run:



*/

 

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