c++ 判断两个double是否相等

#include <stdio.h>
#include <iostream>
#include<math.h>
using namespace std;

bool equal(double num1,double num2)

{

if((num1-num2>-0.000001)&&(num1-num2)<0.000001)
return true;
else return false;

}

int main()
{
double  e;
double f;
e = 0.05-0.075;
f= 0.025-0.05;
if(equal(e,f))
{
printf("%f\n%f",e,f);
printf("=");
}else
{
printf("%f\n%f",e,f);
printf("!=");
}

system("pause");

}