Описать структуру с именем Order

#include <iostream>
#include <iomanip>
#include <algorithm>
 
struct Order {
    long payer;
    long receiver;
    double sum;
};
 
bool bySumDescendant(const Order & a, const Order & b){
    return a.sum > b.sum;
}
 
int main(){
    const int NUM_ORDERS = 8;
    Order orders[NUM_ORDERS], dummy;
 
    for ( int i = 0; i < NUM_ORDERS; ++i ){
        std::cout << "\nOrder #" << ( i + 1 ) << std::endl;
        std::cout << "Payer account: ";
        std::cin >> orders[i].payer;
        std::cout << "Receiver account: ";
        std::cin >> orders[i].receiver;
        std::cout << "Sum: ";
        std::cin >> orders[i].sum;
    }
 
    std::cout << "\nPayers account to calculate amount of pays: ";
    std::cin >> dummy.payer;
    dummy.sum = 0.0;
    for ( int i = 0; i < NUM_ORDERS; ++i )
        if ( dummy.payer == orders[i].payer )
            dummy.sum += orders[i].sum;
    std::cout << dummy.sum << " Ukrain peastro payd from this account." << std::endl;
 
    std::sort(orders, orders + NUM_ORDERS, bySumDescendant);
    std::cout << "\nAll orders by sum descendant:" << std::endl;
    std::cout << "Payer account       Receiver account    Sum" << std::endl;
    std::cout << std::fixed;
    for ( int i = 0; i < NUM_ORDERS; ++i )
        std::cout << std::left << std::setw(20) << orders[i].payer << std::setw(20) << orders[i].receiver << std::setprecision(2) << orders[i].sum << std::endl;
 
    return 0;
}