﻿ C Program: Count the amicable pairs in an array - w3resource

# C Exercises: Count the amicable pairs in an array

## C Numbers: Exercise-26 with Solution

Write a program in C to count the amicable pairs in an array.

Test Data
Input the number of elements to be stored in the array: 4
element - 0: 220
element - 1: 274
element - 2: 1184
element - 3: 1210

Sample Solution:

C Code:

``````# include <stdio.h>
# include <stdlib.h>
# include <stdbool.h>
# include <math.h>

int ProDivSum(int n)
{
int sum = 1;
for (int i=2; i<=sqrt(n); i++)
{
if (n%i == 0)
{
sum += i;

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;
printf("\n\n Count the Amicable pairs in a specific array: \n");
printf(" Sample pairs : (220, 284)(1184,1210) (2620,2924) (5020,5564) (6232,6368)... \n");
printf(" ------------------------------------------------------------------------------\n");
printf("\n Input the number of elements to be stored in the array: ");
scanf("%d",&nn);
int arr1[nn];
for(i=0;i<nn;i++)
{
printf(" element - %d: ",i);
scanf("%d",&arr1[i]);
}
int n1 = sizeof(arr1)/sizeof(arr1);
printf(" Number of Amicable pairs presents in the array: %d\n",ChkPairs(arr1, n1));
return 0;
}
```
```

Sample Output:

``` Input the number of elements to be stored in the array: 4
element - 0: 220
element - 1: 274
element - 2: 1184
element - 3: 1210
Number of Amicable pairs presents in the array: 1
```

Flowchart: C Programming Code Editor: