Question

A prime number is called an Additive prime if the sum of its digits is also a prime

number. Write a program that will display the N (user input) number of additive prime numbers

and displays the output in the following format:

Prime number

Sum of its digits

2

2

3

3

...

11

2

using user-defined functions

Sample output:

Enter an integer: 10

Prime number Sum of Digits

2 2

3 3

5 5

7 7

11 2

23 5

29 11

41 5

43 7

47 11

Answer 1

#include <iostream>
#include <iomanip>
#include <math.h>


using namespace std;
bool isPrime(int num) {
	if (num < 2){
		return false;
	}
	if (num == 2 || num == 3){
		return true;
	}
	for (int i = 2; i <= sqrt(num*1.0); i++){
		if (num % i == 0){
			return false;
		}
	}
	return true;
}


int sumDigits(int number){
	int sum = 0;
	while (number != 0) {
		sum = sum + number % 10;
		number = number / 10;
	}
	return sum;
}


int main(){
	int number;
	int counter=0;
	int i=0;
	cout<<"Enter an integer: ";
	cin>>number;
	cout<<"Prime number\tSum of Digits\n";
	while(counter<number){
		int sumD=sumDigits(i);
		if(isPrime(i) && isPrime(sumD)){
			cout<<i<<"\t\t"<<sumD<<"\n";	
			counter++;
		}
		i++;
	}




	cin>>number;
	return 0;
}