okay i need some help making a function that finds the largest prime factor of a number

so far i have a function that finds the primes of a number and a function that finds the factors of a number

bool isPrime(int a)
{


for (int i = 2; i <=(a-1); i++)

if (a % i == 0)

return false;


else
return true;

}

below is what i used to find the factors...not yet a function but i can easily implement it to a function

for (char i = 1; i <= number; i++)
{
if (number % i ==0 )
{
cout<< i<<endl;

}

}

so can someone help me cram these two together making one fucntion that finds the biggest prime factor of a number?

thanks