How to find the nearest perfect of the number?

Question

You are given a number say 111.The perfect squares before the number is 100 and after the number is 121.

But 111-100=11 and 121-111=10. S the answer is 121.

Sample input:478                                                                                                                              Sample input:1000

Sample output:484                                                                                                                           Sample output:969

Answer 1

just use sqrt, round and power function from <cmath> or <math.h>

float nearestPerfectSquare = pow(round(sqrt(number)),2);