operations.h

#include <math.h>

using namespace std;

#define PI 3.14159265

float _tan (float num1)
{
	float result =tan(num1*PI/180);

	return result;
}

float subtract(float num1, float num2)
{
	float result = num1-num2 ;
	return result;
}


float _sin(float rate)
{
    float result,r;
    r=rate/180;
    int i=r;
    if (i-r==0)
    {
        result=0;
    }
    else
    {
        result = sin ((rate*PI)/180);
    }
    return result;
}


double _log(double x)
{
    return (log10(x));
}

double _log(double base, double x) {
    return (double)(log(x) / log(base));
}

double powerfunction(double base, double power){

	double f = base;
	for (int i = 1; i < power; i++)
		f *= base;
	return f;
}


float factorial(float n)
{

    float result=1;


     for (float i =1;i<=n;i++){
         result*=i;}

    return result;
}

double _negate (double num){
	return num*(-1);
}

double add (double n1 , double n2){
	return n1+n2;
}

double root (double num){
	return sqrt(num);
}

double divide(double n1 , n2){
	if(n2!=0)
	    return n1/n2;
	else cout<<"AN error";
	return 0;
}

double absolute (double num){
    return (num<0?-1*num:num);
}

unsigned long long factorial(double num){
	unsigned long long fac=1;
	for(int i = 1 ; i <= num ; i++)
	    fac*=i;
	return fac;
}

long double ln(long double x)
{
   //***********Variable Declarations************/
   long double count = 0;     //Keeps track of the count in the loop
   long double totalValue = 0; //The summation of each polynomial evaluated
   bool reciprocal = false;   //Flag to use if greater than 2
   long double precision = 9;     //The the highest order of polynomial to use.

   if (x > 2.0)   //Use the rule -ln(1/x) == ln(x) to keep accuracy
   {
      x = 1 / x;        //Change to using 1/x rather than x
      reciprocal = true; //Flag as true (sign change is later)
   }

   while (count < precision)
   {
      totalValue += pow(-1, count + 1) * (pow((x-1),count)/count);
      count++;
   }

   if (reciprocal == true)
      totalValue * -1;   //If reciprocal was used multiply by -1 to change sign

   return totalValue;
}

double divide(double num1, double num2)
{
if(num2 == 0)
cout<<"Invalid, the second number must be > 0"<<endl;
double result = num1/num2;
return result;
}