int main() { for(auto sheet : xlnt::load_workbook("book.xlsx")) { std::cout << sheet.get_title() << ": " << std::endl; for(auto row : sheet) { for(auto cell : row) { std::cout << cell << ", "; } std::cout << std::endl; } } xlnt::workbook workbook; for(int i = 0; i < 3; i++) { auto sheet = workbook.create_sheet("Sheet" + std::to_string(i)); for(int row = 0; row < 1000; row++) { for(int column = 0; column < 1000; column++) { sheet[xlnt::cell_reference(column, row)] = row * 1000 + column; } } } workbook.save("book2.xlsx"); }