//	Ex442.cc

//	Sec. 4.4 of lecture
//	FOR-loop 
//			Example: double sum

#include <iostream.h>

main()
{
 int    i,k,n;			// loop index, sum, last index
 double sum_i,sum_k;		// outer and inner sum
 
 cout << endl;
 cout << "  Input n : ";
 cin  >> n;				// read n

 sum_k = 0.0;				// initialize outer sum
 
 for ( k = 1; k <= n; k++)
  {
    sum_i = 0.0;			// initialize inner sum
    for ( i = 1; i <= k; i++)		// last index depends on k !!
     {
        sum_i = sum_i + 1.0/i/i;
     }
    cout << "  Sum (" << k << ") = " << sum_i << endl;
    sum_k = sum_k + sum_i;		// sum_k grows unbounded
//    sum_k = sum_k + sum_i/n;		// sum_k is bounded
  }

 cout << endl;
 cout << "  Double-Sum (" << n << ") = " << sum_k << endl; 
 cout << endl;

}