Please help with prime number.

[18RGNwbp]

Write your question here.

  #include <iostream>
#include <iomanip>
#include <cmath>
#include <cstdlib>

using namespace std;

int main()
{
    // Function A: Numbers divisible by 5, 6, 9, and 10
	int k, Hold;
	k = 0;
	while ( k < 20 )
	{
		Hold = rand();
		if ( Hold > 101 && Hold < 3000 && Hold % 5 == 0 && Hold % 6 == 0 && Hold % 9 == 0 && Hold % 10 == 0 )
		{
			cout << setw(4) << Hold << endl;
			k = k+1;

		}

	}   
}

However, can someone please help me with code on how to calculate prime numbers. There must be two different functions: One must be a list of 20 random, prime numbers greater than 100 and less than 2000. The other function must be a list od 20, random, prime numbers greater than 200 and less than 5000.
Please try to use code, similar to the one shown above.

[eyenrique]

with this code you can calculate prime numbers between the range that you want. However i can't do it randomly!

#include<iostream>
using std::cout;
using std::cin;
using std::endl;

#include<cmath>
using std::sqrt;

bool prime(int number); //function prototype

int main(){

int numberOfPrimes=0;
int firstNumber;
int secondNumber;

cout<<"Find primes numbers from: ";
cin>>firstNumber;
cout<<"To(greater than the first number please!): ";
cin>>secondNumber;
cout<<'\n';

for(int number=firstNumber;number<=secondNumber;number++){
        if(prime(number)==true){
                ++numberOfPrimes;
                cout<<"["<<number<<"] is prime"<<endl;
        }//end if
}//end loop for
cout<<"\nFound: "<<numberOfPrimes<<endl;

return 0; //indicates success
}//end main

bool prime(int number){
        bool isPrime=false;
        int divisibleNumbers=1;
        int limit=sqrt(number);
        int notPrime=0;
        for(int counter=1;counter<=limit;counter++){
                if(number%counter==0)
                        if(counter==1){
                                divisibleNumbers++;
                        }else{
                                notPrime++;
                        }//end if...else
        }//end loop for
        if((divisibleNumbers==2&&notPrime==0)&&number!=1){
                isPrime=true;
        }//end if
        return isPrime;
}//end function prime 

Find primes numbers from: 2
To(greater than the first number please!): 10

[2] is prime
[3] is prime
[5] is prime
[7] is prime

Found: 4