Условие

 
#include<iostream>
using namespace std;
int main()
{int a,b,c;
double sum,sum1;
cout<<"Tazi programa she izchisli sumata na proizwedeniqta \n";
cout<<"ot 1 do wywedenoto ednocifreno chislo\n";
cout<<"Sumata se formira taka 1*2 + 2*3*4 +...+n*(n+1)*(n+2)*..*2*n \n";
cout<<"Primer 4 Izhod 7106\n";
cout<<"Wywedete chislo: ";
   cin>>c; //wywevda se chisloto
   c%=10; //da ne se izkusqt da wywedat chislo>9
   sum=0; //nachalnata stojnost pri sumirane e winagi nula
   for (a=1; a<c+1; a++)
    { //tqlo na 1-wiq cikal
      sum1=1; //nachalnata stojnost pri natrupwane na proizwdenie e 1
      for (b=a; b<2*a+1; b++)
       { //tqlo na 2-riq cikal
 sum1 *= b; // sum1 = sum1*b
 cout<<"Mevdinnata suma za "<<a<<": "<<sum1<<"\n";
       } //kraj na wytreshniq cikyl
     sum+=sum1; //sum = sum + sum1
     cout<<endl;
    }//kraj na wynshniq cikyl
    cout<<"Krajnata suma e: "<<sum<<"\n";
system("pause");
  return 0;
} //kraj na programa wloveni cikli