Lab_2013_1

#include <cstdlib>
#include "funciones.h"
#include <iostream>

using namespace std;

int main(int argc, char** argv) {
    int precision = 3;
    double val;
    double resp;
    //newPrec = 1/(potencia1(10,precision));
    //cout << newPrec << endl;
    val = pi(4);
    cout << val << endl;

    resp = coseno(45,1,4);
    cout << resp << endl;

    return 0;
}

#ifndef FUNCIONES_H
#define FUNCIONES_H

double pi(int);
double potencia1(double, int);
double abs(double);
double coseno(double, double, int);

#endif /* FUNCIONES_H */

#include "funciones.h"

double pi(int precision) {
    double piR, piRAnt, newPrec;
    int ind1 = 2, ind2 = 1;
    int condicion = 1;
    piR = 2;
    int bandera = 0;
    newPrec = 1 / (potencia1(10, precision)); // 0.001

    while (condicion) {
        piRAnt = piR;
        piR = piR * ind1 / ind2;

        if (bandera){
            ind1 += 2;
            bandera = 0;
        }
        else{
            ind2 += 2;
            bandera = 1;
        }
        if (abs(piRAnt - piR) > newPrec) {
            condicion = 1;
        } else{
            condicion = 0;
            //piRAnt = piR;
        }
    }
    return piRAnt;
}

double coseno(double x, double tipo, int precision){
    //Tipo = 0, entonces el angulo esta en radianes
    //Tipo = 1, entonces el angulo esta en sexagesimales
    if(tipo == 1) x *= (pi(precision))/180;

    //Transformando la precision
    double pre = 1;
    for(int i=1; i<=precision; i++)
        pre /= 10;

    double resp1 = 1.0;
    double resp2 = 1.0;
    double a = 1.0;
    double b = 1.0;
    bool resta = true;
    while(1){
        a *= x*x;
        if(b == 1.0) b = 2;
        else b *= ((b+1)*(b+2));
        if(resta){
            resp2 -= (a/b);
            resta = false;
        }
        else{
            resp2 += (a/b);
            resta = true;
        }

        if(abs(resp1-resp2) < pre) break;
        else resp1 = resp2;

    }
    return resp2;
}


double potencia1(double base, int exp) {
    double pot;
    int i;
    pot = 1;
    for (int i = 1; i <= exp; i++) {
        pot = pot * base;
    }
    return pot;
}

double abs(double x) {
    if (x >= 0)
        return x;
    else return (-1 * (x));
}