Интеграл BC++

#include <iostream.h>
#include <math.h>
main()
{
double x,a,b,n,y,h,f,k,t;
float x0;xn;y0;yn;
cout<<a;
cin>>a;
cout<<b;
cin>>b;
cout<<k;
cin>>k;
h=(b-a)/n;
cin>>n;
for (i=1; i<=n; i++);
f=(a+h)*(i-0,5);
y=k*f+b;
t=(y-b)/k;
return 0;

#include <iostream>
#include <cmath>
 
using std::cout;
using std::cin;
using std::pow;
 
double function(double x)
{
    return 4 - x * x;
}
 
int main(int argc, char* argv[])
{
    double a;
    cout << "Enter a:";
    cin >> a;
    
    double b;
    cout << "Enter b:";
    cin >> b;
    
    double area = 0;
    for (double x = a; x < b; x += 0.0001)
    {
        area += function(x + 0.00005) * 0.0001;
    }
 
    cout << area << '\n';
 
    return 0;
}

#include <iostream.h>
#include <math.h>
main()
{
int i, x;
int n;
float a,b,s,y,h;
cout«"\n Input integral:";
cout«"a";
cin»a;
cout«"b";
cin»b;
cout«"n";
cin»n;
cout«"y";
cin»y;
h=(b-a)/n;
x=a;
for(i=0; i<=n-1; i++)
{
x=x+h;
s=h+y*(x+h/2);
}
cout«"\n Result"«s;
return 0;
}

#include <cmath>
#include <iostream>
using namespace std;
 
int main()
{
    //Âîò íàøå òàáëè÷íîå çàäàíèå ôóíêöèè
    double x[] = {-3,-2.2,0,3.4,5.2,6.7,12.8};
    double y[] = {20,-6.7,1,1.2,4.3,-8,3.6};
 
    double s   = 0;//Ñîáñòâåííî è áóäåò íàêàïëèâàòü çíà÷åíèå ñóììû
    //ïëîùàäåé ýëåìåíòàðíûõ ïðÿìîóãîëüíèêîâ, 
    //ò.êå âêîíöå áóäåò ñîäåðæàòü çíà÷åíèå èíòåãðàëà
    
    int i;//Ñ÷¸ò÷èê
    //Îïðåäåëÿåì ðàçìåðíîñòü ìàññèâà
    int n = sizeof(x)/sizeof(x[0]);
    //Âû÷èñëåÿì èíòåãðàë ìåòîäîì ïðÿìîóãîëüíèêîâ
    for(i = 1; i < n - 1; i++)
        s += y[i - 1]*(x[i] - x[i - 1]);
    cout<<"Integral = "<<s<<endl;
    return 0;
}