calling structure into main function-CodePudding

I am writing code to find two prime numbers. For this I need to return two values from the function primefactor(). I am using a structure to return the two values.

#include <stdio.h>
#include<stdbool.h>

struct tuple  {
    long int prime1,prime2;
};

typedef struct tuple primefind;

bool isPrime(int n) 
{ 
    // Corner case 
    if (n <= 1)  return false; 
  
    // Check from 2 to n-1 
    for (int i=2; i<n; i  ) 
        if (n%i == 0) 
            return false; 
  
    return true; 
} 

long int nextPrime(long int n)
{
    // Base case
    if (n <= 1)
        return 2;
    long int prime = n;
    bool found = false;
    // Loop continuously until isPrime returns
    // true for a number greater than n
    while (!found)
    {
        prime  ;
        if (isPrime(prime))
            found = true;
    }
    return prime;
}

primefind primeFactor(long int n)
{
    primefind tuple1;
    long int p, q;

    p = 2;
    while (p <= (n / p))
    {
        if (n % p == 0)
        {
            q = n / (p);
            break;
        }
        p = nextPrime(p);
    }

    tuple1.prime1 = p;
    tuple1.prime2 = q;
    return tuple1;
}


int main()
{
    
    
    return 0;
}

How could I print the value of p,q in the main function which are the two variables of primeFactor function?

Thank you.

CodePudding user response：

Anything wrong with the obvious solution?

primefind primes = primeFactor(n);
printf("%ld %ld\n", primes.prime1, primes.prime2);

You may also consider changing your approach and using function parameters for your return values:

void primeFactor(long int n, long int *prime1, long int *prime2)
{
    // ...
    *prime1 = 7;
    *prime2 = 11;
    return;
}

Also please consider only checking factors up to the square root of your number.

CodePudding user response：

Just create an object (struct) in your main() function and assign it to the return value of primeFactor() function.

int main()
{
    primefind data =  primeFactor(50);
    printf("prime1 = %ld\n", data.prime1);
    printf("prime2 = %ld\n", data.prime2);
    return 0;
}

CodePudding user response：

like this

   primefind result = primeFactor(42);
   printf("%ld %ld \n", result.prime1, result.prime2);