#include 

int main() {
        xlnt::workbook wb;
        auto ws = wb.active_sheet();
        ws.cell("A1").value(1);
        ws.cell("A2").value(2);
        ws.cell("A3").value(3);
        ws.cell("A4").formula("=SUM(A1:A3)");
        wb.save("book.xlsx");
}