请问怎么运算的?请把步骤写一下?

Question

main(){ printf("%d \n ",fun(9));}int fun ( int x ){ int p;  if ( x == 0 || x == 1 ) {  return ( 3 ); } else  {  p = x - fun( x - 2 ); }}运行结果为3!请大神破解!谢谢!

Answer 1

递归啊

Answer 2

递归调用啊，只需要一步一步跟进去然后一步一步走出来就好了啊