Colin dit :

Yes – sprintf(« %.2f », size), for example, used for filling the Size column, is really slow. « %.2f » is a format modifier meaning « float number with two digits after the comma ».

It’s faster to use sprintf(« %d.%d », a, b) and use a simple integer division to get the part before the comma, then a multiplication of the remainer by the rest, then a re-division to keep one number after the comma. – Faster enough to warrant the hassle !