What printf does?

Question

here's code:

#include <stdio.h>
int main()
{
long long i, n = 600851475143;
for (i = 3; n > 1; i += 2)
while (n % i == 0)
n /= i;
printf("%lld\n", i - 2);
return 0;
}

What is in printf and what it means?

Answer 1

%lld is used to print long long integer.

Answer 2

when i change it to std::cout << n; it outputs 1, and why in printf is i - 2 ?

Answer 3

Run the while loop like this, it will make more sense.

while (n % i == 0) {
n /= i;
printf("%lld is divided by %lld\n", n,i);
}

Answer 4

printf function prints the text on console..it is used in c language