how to think c++ output about this code

[ilovecoffee]

I can't understand the funz function, how I can think this code?
i have only this idea:
12 is != 0
return is 12+funz(12,10)
then x=12 y=10
10 is != 0
return is 12+10+funz(10,2)
then x=10 y=2
2 is != 0
return is 12+10+2+funz(2, 0)
then x=2 y=0
0 is = 0
return x (26)
t=26
that's right?

  #include <iostream>

using namespace std;

int funz(int, int);

int main()
{
    int a=10, b=12, t;
    t = funz(a, b);
    cout << "t = " << t << endl;
    return 0;
}

int funz(int x,int y)
{
    if (y!=0){
            cout << y+funz(y, x%y) << endl;

        return (y+funz(y, x%y)); }
    else
        return x;
}

[JLBorges]

#include <iostream>

int funz(int, int);

int main()
{
    std::cout << "0. in main\n" ;

    int a = 10, b = 12 ;
    const int t = funz(a, b) ;

    std::cout << "0. back in main: t == " << t << '\n' ;
}

std::ostream& spaced_cout( int n )
{
    for( int i = 0 ; i < n*8 ; ++i ) std::cout << ' ' ;
    return std::cout << n << ". " ;
}

int funz( int x, int y )
{
    static int cnt = 0 ;
    ++cnt ;

    spaced_cout(cnt) << "enter funz( " << x << ", " << y << " )\n" << std::flush ;

    if( y!=0 )
    {
         spaced_cout(cnt) << "call funz( " << y << ", " << x << '%' << y << " )\n" ;
         const int v = funz( y, x%y ) ;
         spaced_cout(cnt) << "return " << y << " + " << v << " == " << y+v << '\n' ;

         --cnt ;
         return y+v ;
    }
    else
    {
         spaced_cout(cnt) << "return " << x << '\n' ;

         --cnt ;
         return x ;
    }
}

0. in main
        1. enter funz( 10, 12 )
        1. call funz( 12, 10%12 )
                2. enter funz( 12, 10 )
                2. call funz( 10, 12%10 )
                        3. enter funz( 10, 2 )
                        3. call funz( 2, 10%2 )
                                4. enter funz( 2, 0 )
                                4. return 2
                        3. return 2 + 2 == 4
                2. return 10 + 4 == 14
        1. return 12 + 14 == 26
0. back in main: t == 26

http://coliru.stacked-crooked.com/a/0d72817dd81e1afc