--Originally published at Future Queen of C++

I used one of my older WSQ to complete this, for the rest of the WSQ, I made a funtion called Euler of type double, which calculates the number with the formula I got from a quick google research

After learning what means what in that formula, I just created the main funtion where it asks you how many decimals would you like in the answer of Euler, the number of decimals entered must be in decimals.