Practice: Floats and Doubles

Ten problems with real numbers — divisions, square roots and answers with a fractional part.

• At least one side of a division has to be a double before it happens: 1.0 * a / b, not a / b.
• Some inputs are fractions themselves, like 1.5 — read them into a double.
• Watch for whole-number division hiding in a formula — 2 / 5 is 0 — and for squares of big coordinates: keep them in long long or double before sqrt.
• sqrt(x) gives a square root as a double; abs gives a distance.
• When the output asks for a number of decimal places, print with cout << fixed << setprecision(k) << x;, where k is how many.