#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <conio.h>
int ccout(double xi, int i, clock_t stop, clock_t start);
void reserveData(void);

double reserveXi, UnlinearFuncData, reserveTime;
int reserveI;

double unlinear_func(double x)
{
    double f;
    f = pow(x,3)-3;
    //f = pow(x,3)+2*x;
    //f = pow(x,3)-x+1;
    return f;
}

double chords(double x1, double x2)
{
    return (unlinear_func(x2)*x1-unlinear_func(x1)*x2)/(unlinear_func(x2)-unlinear_func(x1));
}

double bisection(double x1, double x2)
{
    return (x1+x2)/2;
}

int iter(int imax, int i, double xi, double x1, double x2, int ch, int deb, double e, clock_t start)
{
    int ich;
    clock_t stop;

    if (i>imax)
    {
        printf("\nExceeded max number of i(iterations)!\n\nWhat we should do?\n");
        printf("1.Continue with the same number of i\n2.Run to find a solution\n3.Exit and print current result\nYour choose: ");
        scanf("%d", &ich);
        switch(ich)
        {
        case 1:
            return i-imax;
            break;

        case 2:
            if (ch==1)
            {

                do
                {
                    xi=chords(x1, x2);

                    if (deb==1)
                    {
                        stop=clock();
                        ccout(xi, i, stop, start);
                        printf("x1=%lf    x2=%lf\n", x1, x2);
                    }

                    i++;

                    if (unlinear_func(xi)*unlinear_func(x1)<0) x2=xi;
                    else
                    {
                        if (unlinear_func(xi)*unlinear_func(x2)<0) x1=xi;
                    }

                }
                while (e<fabs(unlinear_func(xi)));
                stop=clock();

                printf("\n(!)Final: \n");
                stop=clock();
                ccout(xi, i=0, stop, start);
                exit(0);

            }
            else
            {
                if (ch==2)
                {
                    do
                    {
                        xi=bisection(x1, x2);

                        if (deb==1)
                        {
                            stop=clock();
                            ccout(xi, i, stop, start);
                            printf("x1=%lf    x2=%lf\n", x1, x2);
                        }

                        i++;

                        if (unlinear_func(xi)<0) x1=xi;
                        else
                        {
                            if (unlinear_func(xi)>0) x2=xi;
                        }

                    }
                    while(e<fabs(x1-x2));

                    printf("\n(!)Final: \n");
                    stop=clock();
                    ccout(xi, i=0, stop, start);
                    exit(0);

                }
            }

            break;

        case 3:
            reserveData();
            //stop=clock(); Old
            //ccout(xi, i=0, stop, start);
            exit(0);
            break;

        default:
            printf("\nBad answer!");
            exit(0);
            break;
        }
    }
}

int ccout(double xi, int i, clock_t stop, clock_t start)
{
    reserveXi = xi;
    UnlinearFuncData = unlinear_func(xi);
    reserveTime = (stop-start)/CLK_TCK;
    printf("\n\t\t\t\t.::-Result-::.");
    printf("\nRoot value(Xi) = %.8lf", xi);
    printf("\nFunction value = %.8lf", UnlinearFuncData);
    if (i==0) ;
    else
    {
        reserveI = i;
        printf("\nIterations value = %d", reserveI);
    }
    printf("\nElapsed time: %.10f seconds\n", reserveTime);
    return 101;
}

void reserveData(void) {
    printf("\n\t\t\t\t.::-Result-::.");
    printf("\nRoot value(Xi) = %.8lf", reserveXi);
    printf("\nFunction value = %.8lf", UnlinearFuncData);
    if (reserveI==0);
        else
        {
            printf("\nIterations value = %d", reserveI);
        }
        printf("\nElapsed time: %.10f seconds\n", reserveTime);
}

int repeat(int povt)
{
    char Y_n;

    printf("\nDo you want to start program again?(Y/n)");
    fflush(stdin);
    scanf("%c", &Y_n);

    switch (Y_n)
        {
            case 'Y':
                povt=1;
                printf("Ok, press something...");
                break;

            case 'y':
                povt=1;
                printf("Ok, press something...");
                break;

            case 'N':
                return 0;


            case 'n':
                return 0;


            default:
                printf("Wrong answer. Program will finish...\n");
                return 0;

            }
return povt;
}

int main()
{
    double x1, x2, e, xi;
    int i=0, imax, ch, povt=0, prvr, deb;
    clock_t start, stop;

    printf("\t\t+++_Calculating_of_nonlinear_equation_+++\n\n");

    do
    {
        if (povt==1)
        {
            getch();
            system("cls");
        }

        povt=0;

        do
        {
            prvr=0;
            printf("Enter x1: ");
            fflush(stdin);
            scanf("%lf", &x1);

            printf("Enter x2: ");
            fflush(stdin);
            scanf("%lf", &x2);

            if (unlinear_func(x1)*unlinear_func(x2)>0)
            {
                printf("Wrong x1 or x2. Try again!\n");
                prvr=1;
            }
        }
        while(prvr>0);

        do
        {
            prvr=0;
            printf("Enter allowable error(E): ");
            fflush(stdin);
            scanf("%lf", &e);
            if (e<pow(10,-5) || e>pow(10,-3))
            {
                printf("E must be from 10^-5 to 10^-3 Try again!\n");
                prvr=1;
            }
        }
        while(prvr>0);

        do
        {
            prvr=0;
            printf("Enter max number of iterations(i): ");
            fflush(stdin);
            scanf("%d", &imax);
            if (imax<=0)
            {
                printf("Max 'i' must be more then 0! Try again\n");
                prvr=1;
            }
        }
        while(prvr>0);

        printf("\nSelect method:\n\n1.Chords\n2.Bisection\nYour choose will be: ");
        fflush(stdin);
        scanf("%d", &ch);

        switch(ch)
        {
        case 1:
            printf("\n\t\t\tSelected method of chords\n\n");

            printf("Activate debugging mod?(1-yes/2-no): ");
            scanf("%d", &deb);

            if (deb==1) printf("\n\t\t\t\tDebugging mod status: [ON]\n\n");
            else printf("\n\t\t\t\tDebugging mod status: [OFF]\n\n");

            start=clock();
            do
            {
            xi=chords(x1, x2);
            i++;
            i=iter(imax, i, xi, x1, x2, ch, deb, e, start);

            if (deb==1)
            {
                ccout(xi, i, stop, start);
                printf("x1=%lf    x2=%lf\n", x1, x2);
            }

            if (unlinear_func(xi)*unlinear_func(x1)<0) x2=xi;
            else
            {
                if (unlinear_func(xi)*unlinear_func(x2)<0) x1=xi;
            }

            }
            while (e<fabs(unlinear_func(xi))); // f(xi)<=E --> End of cycle
            stop=clock();

            ccout(xi, i, stop, start);

            break;

        case 2:
            printf("\n\t\t\tSelected method of bisection\n\n");

            printf("Activate debugging mod?(1-yes/2-no): ");
            scanf("%d", &deb);

            if (deb==1) printf("\n\t\t\t\tDebugging mod status: [ON]\n\n");
            else printf("\n\t\t\t\tDebugging mod status: [OFF]\n\n");

            start=clock();
            do
            {
            xi=bisection(x1, x2);
            i++;
            i=iter(imax, i, xi, x1, x2, ch, deb, e, start);

            if (deb==1)
            {
                ccout(xi, i, stop, start);
                printf("x1=%lf    x2=%lf\n", x1, x2);
            }

            if (unlinear_func(xi)<0) x1=xi;
            else
            {
                if (unlinear_func(xi)>0) x2=xi;
            }

            }
            while(e<fabs(x1-x2));
            stop=clock();

            ccout(xi, i, stop, start);

            break;

        default:
            printf("\nBad answer! Try again!");
            break;
        }

povt=repeat(povt);
    }
    while(povt==1);

    return 0;
}