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.

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[0]);
		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:

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