#include <iostream>
#include <math.h>
 
using namespace std;
 
double round(double dValue, int nCount)
{
  double dSign = dValue < 0 ? -1 : 1;
  double dPow = pow((double)10., nCount); //лучше иметь предвычисленные значения
  double eps = 0.001;
  return  dSign * (floor(fabs(dValue) * dPow + 0.5 + eps) / dPow);
}
 
void test(double v, int c)
{
   printf("round(%.15lf, %d) = %.15lf\n", v, c, round(v, c));
}
 
int main()
{
	test(4.725, 2);
	test(4.724, 2);
	test(4.7248, 2);
	test(4.7249, 2);
	test(4.72498, 2);
	test(4.724989, 2);
	test(4.7249899999, 2);
	test(4.72499, 2);
	test(4.724999, 2);
	return 0;
}

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