Function problem

Question

#include <iostream>
using namespace std;

int foo (int x) { // becomes int foo (int 4), or int foo (4) --> same thing right?
if (x<=1) // this evaluates to false
return 1;
return foo (x-1)*x; // is the value 4 assigned to x-1 or to x?
} // are we dealing with a recursion or no?

int main () {
cout << foo(4);
}

// How does this output evaluate 24 (the correct output)?
// I calculated it to be 12... by assigning 4 to x in line ' return foo (x-1)*x; '

Answer 1

Yes it is a recursion...
When first the function executes
We get, foo(3)*4
and for second iteration foo(2)*3*4
And for third iteration foo(1)*2*3*4
since we get x= 1 then if condition get true and returns 1
So now we have 1*2*3*4 results to 24

Answer 2

Solus you are not returning (x-1)*x instead you are returning " foo(x-1)*x "

Just like Мг. Кнап🌠 already said, this process is known as recursion (when a function calls itself).

This function is recursively calculating factorial of a number.