#include "integrate.h"
#include "ui_integrate.h"
#include "math.h"
#include <cmath>
#include <time.h>
#include "fact.h"

integrate::integrate(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::integrate)
{
    ui->setupUi(this);
}

integrate::~integrate()
{
    delete ui;
}
float answtrapeze=0;
float trapeze(float int1,float int2,int n,float h,float a)
{
    float x[n],f[n];
    x[0]=a;
    f[0]=sin(x[0]);
    for(int i=1;i<n+1;i++){
        x[i]=x[i-1]+h;//заполняем иксы
        f[i]=sin(x[i]);//считаем функцию sin x
    }
    for(int i=1;i<n;i++)
        int2+=f[i];
    int2=(int2*2+f[0]+f[n])*h/2;//считаем интеграл
    if((fabs(int2-int1))/3<0.01){
        answtrapeze=int1+fabs(int2-int1)/3;//если погрешность < 0.01, то это ответ
        return answtrapeze;
    }
    else{
        int1=int2;//если нет, то h=h/2, n=2*n
        int2=0;
        trapeze(int1,int2,n*2,h/2,a);
    }
}
float answsimpson=0;
float simpson(float int1,float int2,int n,float h,float a)
{
    float x[n],f[n];
    x[0]=a;
    f[0]=sin(x[0]);
    for(int i=1;i<n+1;i++){
        x[i]=x[i-1]+h;
        f[i]=sin(x[i]);
    }
    for(int i=1;i<n;i++)
    {
        if(i%2==1)
        int2+=(4*f[i]);
        else
            int2+=(2*f[i]);
    }
    int2=(int2+f[0]+f[n])*h/3;
    if((fabs(int2-int1))/15<0.01){
        answsimpson=int1+fabs(int2-int1)/15;
        return answsimpson;
    }
    else{
        int1=int2;
        int2=0;
        simpson(int1,int2,n*2,h/2,a);
    }
}
float answnewton=0;
float newton(float int1,float int2,int n,float h,float a)
{
    float x[n],f[n];
    x[0]=a;
    f[0]=sin(x[0]);
    for(int i=1;i<n+1;i++){
        x[i]=x[i-1]+h;
        f[i]=sin(x[i]);
    }
    for(int i=1;i<n;i++)
    {
        if(i%3==0)
            int2+=(2*f[i]);
        else
            int2+=(3*f[i]);
    }
    int2=(int2+f[0]+f[n])*3*h/8;
    if((fabs(int2-int1))/15<0.01){
        answnewton=int1+fabs(int2-int1)/15;
        return answnewton;
    }
    else{
        int1=int2;
        int2=0;
        newton(int1,int2,n*2,h/2,a);
    }
}
void integrate::on_answerButton_clicked()
{
    float int1=0;
    float int2=0;
    int n=2;
    float a=ui->aEdit->text().toFloat();//нижняя граница
    float b=ui->bEdit->text().toFloat();//верхняя граница
    float h=(b-a)/n;//длина разбиения
    clock_t tstart =clock();
    trapeze(int1,int2,n,h,a);
    clock_t tfinish = clock();
    clock_t sstart = clock();
    simpson(int1,int2,n,h,a);
    clock_t sfinish = clock();
    clock_t nstart = clock();
    newton(int1,int2,n,h,a);
    clock_t nfinish = clock();
    ui->TrapezeEdit->setText(QString::number(answtrapeze));
    ui->time1Edit->setText(QString::number(tfinish-tstart));
    ui->SimpsonEdit->setText(QString::number(answsimpson));
    ui->time2Edit->setText(QString::number(sfinish-sstart));
    ui->NewtonEdit->setText(QString::number(answnewton));
    ui->time3Edit->setText(QString::number(nfinish-nstart));
}