text: Mean of array generated by products of all pairs of the given array | C ++ program for the above approach ; Function to find the mean of pair product array of arr [ ] ; Store product of pairs ; Generate all unordered pairs ; Store product of pairs ; Size of pairArray ; Store sum of pairArray ; Stores the mean of pairArray [ ] ; Find mean of pairArray [ ] ; Return the resultant mean ; Driver Code ; Given array arr [ ] ; Function Call
code: #include <bits/stdc++.h> NEW_LINE using namespace std ; float pairProductMean ( int arr [ ] , int N ) { vector < int > pairArray ; for ( int i = 0 ; i < N ; i ++ ) { for ( int j = i + 1 ; j < N ; j ++ ) { int pairProduct = arr [ i ] * arr [ j ] ; pairArray . push_back ( pairProduct ) ; } } int length = pairArray . size ( ) ; float sum = 0 ; for ( int i = 0 ; i < length ; i ++ ) sum += pairArray [ i ] ; float mean ; if ( length != 0 ) mean = sum / length ; else mean = 0 ; return mean ; } int main ( ) { int arr [ ] = { 1 , 2 , 4 , 8 } ; int N = sizeof ( arr ) / sizeof ( arr [ 0 ] ) ; cout << fixed << setprecision ( 2 ) << pairProductMean ( arr , N ) ; return 0 ; }