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[SOLVED] Could someone explain how this function works? I've solved when I put the variable num as 5, but something is wrong.

int recursive(int num) { if (num == 1) return 2; return num * recursive(num-1); }

17th Aug 2021, 12:38 PM
mesarthim
mesarthim - avatar
4 Réponses
+ 4
For num = 5. recursive ( 5 ) will return 5 * recursive ( 5 - 1) = 5 * ( 4 * recursive (4-1) ) = 5 * 4 * ( 3 * recursive (3-1)) = 5 * 4 * 3 * ( 2 * recursive (2-1)) = 5 * 4 * 3 * 2 * 2 { as recursive (1) will return 2 } = 240 So the final value returned by recursive (5) should be 240.
17th Aug 2021, 1:07 PM
Arsenic
Arsenic - avatar
+ 3
recursive(5) num*recursive(4) num*recursive(3) num*recursive(2) num*recursive(1). recursive(1) returns 2 recursive(2) returns num*recursive(1) = num*2=2*2=4 recurisve(3) returns num*recursive(2) = num*4=3*4=12 recurisve(4) returns num*recursive(3) = num*12=4*12=48 revursive(5) returns num*recursive(4) =num*48=5*48=240 functions were pushed onto the stack and then popped off . Refer to the following video if you want to see visualization for it . https://youtu.be/AIwxbJ5mP8M
17th Aug 2021, 1:11 PM
Abhay
Abhay - avatar
+ 1
Thanks for effort! Arsenic
17th Aug 2021, 1:19 PM
mesarthim
mesarthim - avatar
0
Thanks for effort! Abhay
17th Aug 2021, 1:19 PM
mesarthim
mesarthim - avatar