# C++ Programming Code Examples

## C++ > Arrays and Matrices Code Examples

### Write a program in C++ to count the Amicable pairs in an array

``` Write a program in C++ to count the Amicable pairs in an array #include <bits/stdc++.h> using namespace std; int ProDivSum(int n) { int sum = 1; for (int i=2; i<=sqrt(n); i++) { if (n%i == 0) { sum += i; // To handle perfect squares if (n/i != i) sum += n/i; } } return sum; } bool chkAmicable(int a,int b) { return(ProDivSum(a) == b && ProDivSum(b) == a); } int ChkPairs(int arr[],int num1) { int ctr = 0; for (int i=0; i<num1; i++) for (int j=i+1; j<num1; j++) if (chkAmicable(arr[i], arr[j])) ctr++; return ctr; } int main() { int nn; int n, i, j, ctr; cout << "\n\n Count the Amicable pairs in a specific array: \n"; cout << " Sample pairs : (333, 296)(1288,1365) (2784,2458) (5789,5636) (6115,6886)... \n"; cout << " ------------------------------------------------------------------------------\n"; cout << "\n Input the number of elements to be stored in the array: "; cin>>nn; int arr1[nn]; for(i=0;i<nn;i++) { cout<<"element - "<<i<<": "; cin>>arr1[i]; } int n1 = sizeof(arr1)/sizeof(arr1[0]); cout <<" Number of Amicable pairs presents in the array: "<< ChkPairs(arr1, n1) << endl; return 0; } ```