#ifndef LABA9_DECLARATION_H
#define LABA9_DECLARATION_H

#include <iostream>

template <typename T, int N>

class SumSeq {
private:
    int len;
    T data[N], results[N];
public:
    SumSeq<T, N> operator+=(SumSeq &x) {
        for (int i = 0; i < N; i++) {
            data[i] += x.data[i];
            for (int j = 0; j <= i; j++) results[i] += x.data[j];
        }
        return *this;
    }
    SumSeq<T, N> operator*=(T x) {
        for (int i = 0; i < N; i++) {
            data[i] *= x;
            results[i] *= x;
        }
        return *this;
    }
    T operator()(int a, int b) {
        return (a == 0) ? results[b] : results[b] - results[a - 1];
    }
    SumSeq(T dat[N]) {
        for (int i = 0; i < N; i++) data[i] = dat[i];
        len = N;
        results[0] = data[0];
        for (int i = 1; i < N; i++) results[i] = results[i - 1] + data[i];
    }
    void print() {
        for (int i = 0; i < len; i++) std::cout << data[i] << ' ';
        std::cout << std::endl;
    }
};

#endif

----------------------------------------------

#include <iostream>
#include "declaration.h"

using namespace std;

int main() {
    int xx[3] = {1, 2, 3};
    SumSeq<int, 3> x(xx);
    int yy[3] = {4, 5, 6};
    SumSeq<int, 3> y(yy);
    x += y;
    x *= 10;
    x.print();
    cout << x(1, 2) << endl;
    return 0;
}