Post #63

// Arifmetik progressiyaning yig'indisi? // 1-had, ayirma // int a, d, n, S; // cout<<"a1 = "; cin>>a; // cout<<"d = "; cin>>d; // cout<<"n = "; cin>>n; // S = (2*a+d*(n-1))*n/2; // cout<<"S = "<<S<<endl;