MATH AND C++

#include <iostream>
#include <Windows.h>
#include <math.h>
using namespace std;
#define pi 3.14159265
#define radian ( 180 / pi )

double factorial( double n ) {
	if ( n < 1 ) {
		return 1;
	}

	double r = 1;
	for( double i = 1; i <= n; i ++ ) {
		r *= i;
	}

	return r;
}
double exponent( double n , double e ) {
    double r = n;
    for( double i = 0; i < e - 1; i ++ ) {
        r *= n;
    }

    return r;
}
double sign( double n ) {
	return ( n > 0 ) - ( n < 0 );
}
double sqr( double x ) {
	return x * x;
}
double pointdir( double x1 , double y1 , double x2 , double y2 ) {
	return atan2( y2 - y1 , x2 - x1 ) * radian;
}
double pointdist( double x1 , double y1 , double x2 , double y2 ) {
	return sqrt( sqr( x2 - x1 ) + sqr( y2 - y1 ) );
}
double pointdist3d( double x1 , double y1 , double z1 , double x2 , double y2 , double z2 ) {
	return sqrt( sqr( x2 - x1 ) + sqr( y2 - y1 ) + sqr( z2 - z1 ) );
}
double lendirx( double l , double d ) {
	return l * cos( d * radian );
}
double lendiry( double l , double d ) {
	return l * sin( d * radian );
}
double lendirz( double l , double d ) {
	return l * sin( d * radian );
}
double clamp( double val , double min , double max ) {
	return ( ( val <= min ) * min ) + ( ( val >= max ) * max ) + ( ( val > min && val < max ) * val );
}
double neg( double x ) {
	return x * ( ( ( x < 0 ) * 1 ) + ( ( x > 0 ) * -1 ) );
}
double aspect_ratio( double w , double h ) {
	return w / h;
}
double scale_factor( double w ) {
	return 1 / w;
}
double readbit( double byt , double bit ) {
	return ( int( byt ) & int( exponent( 2 , 7 - bit ) ) ) > 0;
}
double buildbit( double bt1 , double bt2 , double bt3 , double bt4 , double bt5 , double bt6 , double bt7 , double bt8 ) {
	return ( 128 * bt1 ) + ( 64 * bt2 ) + ( 32 * bt3 ) + ( 16 * bt4 ) + ( 8 * bt5 ) + ( 4 * bt6 ) + ( 2 * bt7 ) + ( 1 * bt8 );
}
double fixrotation( double rot ) {
	int fix = rot + ( ( rot > 360 ) * -360 ) + ( ( rot < 0 ) * 360 );
	if ( fix > 360 || fix < 0 ) { return fixrotation( fix ); }
	return fix;
}

int main() {
	cout << pointdir( 0 , 0 ,  -1 , 1 ) << endl;
	cout << pointdist( 0 , 0 , 5 , 5 ) << endl;
	cout << pointdist3d( 0 , 0 , 0 , 5 , 5 , 5 ) << endl;
	cout << sign( 10 ) << endl;
	cout << exponent( 5 , 2 ) << endl;
	cout << factorial( 5 ) << endl;
	cout << sqr( 6 ) << endl;
	cout << clamp( 8 , 0 , 16 ) << endl;
	cout << neg( -1 ) << neg( 1 ) << endl;
	cout << buildbit( 0 , 1 , 1 , 0 , 1 , 0 , 0 , 1 ) << endl;
	cout << readbit( 192 , 0 ) << endl;
	cout << fixrotation( 365 * 3 ) << endl;

	double xx;
	cin >> xx;
}