### C program to find if two numbers are Amicable or not :

Two numbers are known as *Amicable numbers* if the sum of proper divisors of one number is equal to the other number. In this tutorial, we will check how to find if two numbers are *Amicable* or not using *c programming language*. The algorithm we are going to use is as below :

### Algorithm :

- First ask the user to enter
*both numbers.* - Find the sum of all
*divisors*for both numbers. - Finally check if the
*sum of the divisors of one number is equal to the other number or not.* - If
*yes*, it is a*Amicable number*and*otherwise not*.

### C program :

```
#include<stdio.h>
int main()
{
//1
int i;
int firstNumber,secondNumber;
//2
int firstDivisorSum = 0;
int secondDivisorSum = 0;
//3
printf("Enter two numbers to check if Amicable or not : ");
scanf("%d %d",&firstNumber,&secondNumber);
//4
for(int i=1;i<firstNumber;i++){
//5
if(firstNumber % i == 0){
firstDivisorSum = firstDivisorSum + i;
}
}
//6
for(int i=1;i<secondNumber;i++){
if(secondNumber % i == 0){
secondDivisorSum = secondDivisorSum + i;
}
}
//7
if((firstNumber == secondDivisorSum) && (secondNumber == firstDivisorSum)){
printf("%d and %d are Amicable numbers\n",firstNumber,secondNumber);
}else{
printf("%d and %d are not Amicable numbers\n",firstNumber,secondNumber);
}
}
```

### Explanation :

*The commented numbers in the above program denotes the steps below :*

- Create one integer
*i*to use in the*loops*and create two more integer variables*firstNumber*,*secondNumber*to store the first and second number. - Create two more integer variables to store the
*sum of the divisors*:*firstDivisorSum*and*secondDivisorSum*. - Ask the user to input both numbers. Store the values in
*firstNumber*and*secondNumber*. - Use one
*for loop*and check for each numbers starting from*1*to*fistNumber -1*. - Check for each number in the loop if it can divide the number
*firstNumber*or not. If yes, add this number to the*firstDivisorSum*. After the loop complets,*firstDivisorSum*contains the sum of all the divisors for*firstNumber*. - Similarly, find the sum of all divisors for the second number and save it in
*secondDivisorSum*. - Finally, check if the
*sum of divisors of one number is equal to the other number or not.*If yes, print that both are*Amicable*numbers. Otherwise they are not.

### Example Output :

```
Enter two numbers to check if Amicable or not : 12 13
12 and 13 are not Amicable numbers
Enter two numbers to check if Amicable or not : 220 284
220 and 284 are Amicable numbers
Enter two numbers to check if Amicable or not : 24 47
24 and 47 are not Amicable numbers
Enter two numbers to check if Amicable or not : 288 822
288 and 822 are not Amicable numbers
```