Output the nth element of the Fibonacci sequence using a recursive and non-recursive method (C language Implementation)

Faipot Series (Italian: Successione di Fibonacci), also translated into Faipot , Fibonacci series , Fermi series , the Golden section of the series .

Mathematically, the faipot sequence is defined in a recursive way:

• {\displaystyle f_{0}=0}
• {\displaystyle F_{1}=1}
• {\displaystyle f_{n}=f_{n-1}+f_{n-2}} (N≧2)

In words, the faipot sequence starts with 0 and 1, and then the Fibonacci coefficients are summed up by the previous two numbers. The first few fee Fibonacci coefficients are:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233 ... (Oeis in the series A000045)

In particular , 0 is not the first, but the 0th.

1#include <stdio.h>2 3 intFIB1 (intn);//non-recursive generation of Fibonacci sequence elements labeled N4 intFIB2 (intn);//recursive generation of Fibonacci sequence elements labeled N5 6 intMain ()7 {8     intN;9printf ("Please input the index of FIB:") ;Tenscanf ("%d", &n); Oneprintf ("The %d fib1 number is%d \ n", N, FIB1 (n)); Aprintf ("The %d fib2 number is%d \ n", N, FIB2 (n)); -     return 0 ; - } the  - intFIB1 (intN) - { -     inti =0 ; +     intA =1 ; -     intb =1 ; +     intresult =0 ; A     if(N <=0) at     { -         return 0 ; -     } -     Else if(N <=2) -     { -         return 1 ; in     } -     Else to     { +          for(i =3; I <= N; i + +) -         { theresult = A +b; *A =b; $b =result;Panax Notoginseng         } -         returnresult; the     } + } A  the intFIB2 (intN) + { -     if(N <=0) $     { $         return 0 ; -     } -     Else if(N <=2) the     { -         return 1;//recursive termination conditionsWuyi     } the     Else -     { Wu         returnFIB2 (n1) + FIB2 (n2) ;//Recursive -     } About}

Output the nth element of the Fibonacci sequence using a recursive and non-recursive method (C language Implementation)