Please trace the c++ program below

#include

using namespace std;

int f (int a);

int main()

{

cout

return 0;

}

int f (int a)

{

if (a==1 || a==2)

return (2);

else

return (f(a-1)+f(a-2));

}

the output is 42.

the tracing is use local and global variable as follows

Variable Scope Value Example: X Y Local: Main Function Local: The fx squared function Global 0 1 3