method 1 v2.0

#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <conio.h>
#include <stdio.h>

using namespace std;
double e=0.01;
double a = 0;
double b = 2;

double f(double x)
{
return (sqrt(pow(x,2)+3)/(x+5));
}

double razrad()
{
     double d,x,y;
    d=(b-a)/4;
    double x0=a;
    double f0=f(x0);
    label:
    double x1=x0+d;
    double f1=f(x1);
    if (f0>f1)
    {
        x0=x1;
        f0=f1;
        if(a<=x0 && x0<=b)
            goto label;
    }
    if (fabs(d)<=e)
    {
        x=x0;
        y=f(x0);
    }
    else
    {
        x0=x1;
        f0=f1;
        d=-d/4;
        goto label;
    }
    cout <<"rmin=" << x << endl;
    cout <<"rfmin=" << y << endl;
    return 0;
}

double dihot()
{
    double s=0.001;
    double x1,x2,en,x,y;
    do
    {
    x1=(b+a-s)/2;
    x2=(b+a+s)/2;
    if(f(x1)<=f(x2)) b=x2;
    else a=x1;
    en=(b-a)/2;
    }
    while(en>e);
    x=(a+b)/2;
    y=f(x);
    cout << endl;
    cout << "dmin = " << x << endl;
    cout << "dfmin = " << y << endl;
    return 0;
}

double gold()
{
    double x1,x2,f1,f2,t,l,en,x,y;
    t=(sqrt(5)-1)/2;
	l=b-a;
	x1 = b - t*l;
	x2 = a + t*l;
	f1 = f(x1);
	f2 = f(x2);
    while(l>2*e)
    {
    if(f1<=f2)
	{
		b = x2;
		l=b-a;
		x2=x1;
		f2=f1;
		x1=b-t*l;
		f1=f(x1);
	}
	else
	{
		a=x1;
		l=b-a;
		x1=x2;
		f1=f2;
		x2=a+t*l;
		f2=f(x2);
	}
	}
	x=(a+b)/2;
	y=f(x);
    cout << endl;
    cout << "gmin = " << x << endl;
    cout << "gfmin = " << y << endl;
    return 0;
}

double parabol()
{
	double x1, x2, x3, f1, f2, f3, a1, a2, x, fx, xp;
    x1=(3-sqrt(5))*(b-a)/2;
	x3=(sqrt(5)-1)*(b-a)/2;
    x2=(x1+x3)/2;
    x=0;
    f1=f(x1);
    f2=f(x2);
    f3=f(x3);
    do
    {
    xp=x;
    a1=(f2-f1)/(x2-x1);
    a2=(1/(x3-x2))*( (f3-f1)/(x3-x1) - (f2-f1)/(x2-x1) );
    x=0.5*(x1+x2-(a1/a2));
    fx=f(x);
    if(x1<x<x2<x3)
        if(fx>=f2)
        {
        x1=x;
        f1=f(x1);
        }
        else
        {
        x3=x2;
        x2=x;
        f2=f(x2);
        f3=f(x3);
        }
            else if(x1<x2<x<x3)
            if(fx>=f2)
            {
            x3=x;
            f3=f(x3);
            }
            else
            {
            x1=x2;
            x2=x;
            f1=f(x1);
            f2=f(x2);
            }
    }
    while(abs(xp-x)>e);
    cout << endl;
    cout << "pmin = " << x << endl;
    cout << "pfmin = " << fx << endl;
    return 0;
}


int main()
{
    razrad();
    dihot();
    gold();
    parabol();
    system ("pause");
}