#include<iostream>
#include<math.h>

using namespace std;

const int LE = 20;
const int L = 5 + LE*4;

char* replaceComma(char* a, int length) {
    for (int i = 0; i < length; i++) {
        if (a[i] == ',') a[i] = '.';
    }
    return a;
}

int findStringLength(char* a, int limit) {
    int i = 0;
    while (a[i] != '\0' && ++i != limit);
    return i;
}

char* doubleToString(double a) {
    char* sa = new char[20];
    snprintf(sa, 20, "%.12lf", a);
    return sa;
}

char* moveToRight(char* a, int length) {
    int i = length + 1;

    while (i-- != 1) a[i] = a[i - 1];
    a[0] = ' ';

    return a;
}

char* formatString(const char* a, int desiredLength) {
    char* sa = new char[desiredLength+1];
    sa[desiredLength] = '\0';
    snprintf(sa, desiredLength, "%s", a);
    int numLength = findStringLength(sa, desiredLength);
    int d = desiredLength - numLength;
    for (int i = 0; i < d; i++) {
        sa[numLength + i] = ' ';
    }

    int offset = d / 2;
    for (int i = 0; i < offset; i++) sa = moveToRight(sa, numLength + i);
    return sa;
}

char* formatDouble(double a, int desiredLength = LE) {
    return formatString(doubleToString(a), desiredLength);
}

void printS() {
    for (int i = 0; i < L; i++) printf("-");
    printf("\n");
}

void printHeader(bool s = true) {
    printS();

    printf("|%s|%s|%s|%s|\n",
        formatString(s ? "x" : "e", LE),
        formatString("f(x)", LE),
        formatString("F(x)", LE),
        formatString("delta", LE)
    );

    printS();
}

double getValue(const char* message, bool lock = true) {
    double r;
    char* a = new char[100];
    char* eptr;
    do {
        a = new char[100];
        cout << message << endl;
        cin >> a;
        a = replaceComma(a, 100);

        r = strtod(a, &eptr);
    } while (*eptr != '\0' || (lock && r*r >= 1 || r == 0));
    return r;
}



double fff(double x, double e) {
    double l = -1, c = x;
    double s = c;
    int k = 0, n = 0;
    do {
        n = 2 * k + 1;
        l = c;
        c *= x * x * n / (n+2);
        s += c;
        k++;
    } while (abs(c - l) >= e);

    return 2 * s;
}

double ff(double x, double e) {
    return fff(x / (2 - x), e);
}

double f(double x, double e) {
    double l = -1, c = x / 2;
    double s = c;
    int k = 1;
    do {
        l = c;
        c *= x * k / (k + 2);
        s += c;
        k++;
    } while (abs(c - l) >= e);

    return 1 - s;
}

double F(double x) {
    return ((1 - x) / x) * log(1 / (1 - x));
}

double delta(double f, double F) {
    return abs(f*f - F*F);
}

void printRow(double x, double e) {
    double mf = f(x, e);
    double lf = F(x);
    double d = delta(mf, lf);
    printf("|%s|%s|%s|%s|\n",
        formatDouble(x),
        formatDouble(mf),
        formatDouble(lf),
        formatDouble(d));
}

int main() {
    double xs = 0, xe = 0.9, dx = -0.1, xi = 3, e = -0.00001;
    cout << "((1 - x) / x) * log(1 / (1 - x))" << endl;
    cout << "0 < |x| < 1" << endl;
    xs = getValue("Enter x start");
    xe = getValue("Enter x end");
    dx = getValue("Enter delta x");
    while (e <= 0 || e < 1e-7) {
        e = getValue("Enter e", false);
    }

    xi = getValue("Enter x ideal");
    double x = xs;

    printHeader();
    do {
        printRow(x, e);
        x += dx;
    } while ((xe > xs && dx > 0 && xe > x) || (xe < xs && dx < 0 && x > xe));
    if (fabs(xe - x + dx) > 1e-6) printRow(xe, e);

    printS();
    cout << endl;

    printHeader(false);
    e = 0.1;
    while (e > 1e-7) {
        double mf = f(xi, e);
        double lf = F(xi);
        double d = delta(mf, lf);
        printf("|%s|%s|%s|%s|\n",
            formatDouble(e),
            formatDouble(mf),
            formatDouble(lf),
            formatDouble(d));
        e *= 0.1;
    }

    printS();
    return 0;
}