About trunc function and application

trunc analogy with int

Direct removal function trunc the fractional part of

INT is a function rounding down to the nearest integer.

TRUNC (-5.6) is the integer part of the result (-5)

### INT (-5.6) after the integer part of the result is rounded down (-6)

application:

• End rounding operations
• eg maximum pasture area multiplied by 100 and then round the result of the tail. If you can not build, output -1.

int helen(double a,double b,double c)//海伦公式求面积
{
    if(a+b>c && b+c>a && a+c>b)
    {
        double p=(a+b+c)/2;
        return trunc(sqrt(p*(p-a)*(p-b)*(p-c))*100);
    }
    else return -1;
}