How do I store a 100000*100000 matrix in C++? -

i have 2 vectors a[100000] , b[100000]. want store a[i]*b[j] in matrix. how can in c++?

you can use std::vector<std::vector<your_type>> store result.

int rows = 100000, cols = 100000;  std::vector<std::vector<double>> result; result.resize(rows);  for(int i=0; i<rows; i++) {         result[i].resize(cols); }      for(int i=0; i<rows; i++) {     for(int j=0; j<cols; j++){         result[i][j] = a[i] * b[j];     } } 

or can use linear algebra library, example eigen (you'll may have less code this), will surely more efficient.